Chocolate Sheet Cake Recipe

Oh, chocolate sheet cake. Just the name conjures up images of warm, fudgy goodness, doesn’t it? For years, I’ve been on the hunt for that perfect chocolate cake recipe – one that’s not only incredibly flavorful but also straightforward enough for a weeknight treat or a last-minute celebration. Let me tell you, this recipe by Fiona Dowling is a game-changer. From the moment I mixed the batter to the final, glorious bite, I knew I had stumbled upon something special. My family devoured it, and frankly, I had to hide a piece for myself to enjoy the next day (it’s even better the day after, if you can believe it!). This isn’t just any chocolate cake; it’s the chocolate sheet cake you’ll find yourself making again and again. It’s moist, it’s deeply chocolatey, it’s ridiculously easy, and it’s guaranteed to become a new family favorite. Ready to dive into chocolate heaven? Let’s get baking!

Ingredients

The beauty of this chocolate sheet cake lies in its simplicity. You likely have most, if not all, of these everyday ingredients already in your pantry and refrigerator. Let’s break down what you’ll need for both the cake and the luscious chocolate frosting.

Chocolate Sheet Cake Ingredients

• 2 cups All-Purpose Flour (250 grams): The foundation of our cake! All-purpose flour provides the structure and tenderness we’re looking for. Make sure to measure your flour correctly – spoon it into your measuring cup and level it off with a knife. Scooping directly from the bag can pack the flour and lead to a drier cake. For a slightly richer flavor, you could use cake flour, but all-purpose works wonderfully and keeps things simple. If you’re looking for a gluten-free option, a good quality gluten-free all-purpose blend can be substituted, but you may need to adjust the liquid slightly as gluten-free flours can absorb moisture differently.
• 1/2 cup Cocoa Powder (45 grams): This is where the magic happens – the intense chocolate flavor! Use unsweetened cocoa powder for this recipe. Dutch-processed cocoa powder will give a darker, smoother flavor and a slightly darker cake, while natural cocoa powder will have a brighter, more acidic chocolate taste. Both will work beautifully; it comes down to personal preference. Sifting the cocoa powder is crucial, especially if it’s lumpy, to ensure a smooth batter and no little cocoa clumps in your final cake. Nobody wants a surprise bitter bite!
• 2 cups Granulated Sugar (400 grams), (or 1 3/4 cup for less sweetness): Sugar not only sweetens the cake but also contributes to its moisture and tenderness. Granulated sugar is the standard choice for this recipe. If you prefer a slightly less sweet cake, reducing the sugar to 1 3/4 cups (350 grams) is perfectly acceptable and won’t drastically alter the texture. You could also experiment with using a portion of brown sugar for a slightly deeper, molasses-like flavor, but for this classic recipe, granulated sugar is perfect.
• 2 teaspoons Baking Soda: Baking soda is a leavening agent that reacts with acidic ingredients (like cocoa powder and sour cream in this recipe) to help the cake rise and become light and airy. Make sure your baking soda is fresh – if it’s been sitting in your pantry for a while, test its potency by dropping a pinch into vinegar; it should fizz vigorously.
• 1/2 teaspoon Baking Powder: Baking powder is another leavening agent, but unlike baking soda, it contains its own acid, so it reacts when it comes into contact with liquid and heat. Using both baking soda and baking powder in this recipe ensures a beautifully light and well-risen cake. Again, check the freshness of your baking powder for optimal results.
• 1/4 teaspoon Salt: Don’t underestimate the power of salt in baking! Salt enhances the flavors of all the other ingredients, especially the chocolate. It balances the sweetness and prevents the cake from tasting flat. Use regular table salt or fine sea salt for this recipe.
• 1/2 cup Vegetable Oil (120 ml): Oil is key to the incredible moistness of this sheet cake. Vegetable oil, with its neutral flavor, is a great choice. You could also use canola oil or even melted coconut oil (though this might impart a slight coconut flavor). Avoid using olive oil, as its strong flavor can overpower the chocolate. Oil creates a tender crumb that stays moist for days.
• 2 Large Eggs: Eggs provide structure, richness, and moisture to the cake. Large eggs are the standard size for most baking recipes. Make sure your eggs are at room temperature, as this helps them emulsify better with the other ingredients, resulting in a smoother batter and a more tender cake.
• 2 teaspoons Vanilla Extract: Vanilla extract enhances the chocolate flavor and adds a touch of warmth and complexity. Use pure vanilla extract for the best flavor. If you’re feeling adventurous, you could try using vanilla bean paste or even scrape the seeds from a vanilla bean for an even more intense vanilla flavor.
• 1/2 cup Milk (120 ml), (Whole milk is best, 2% works too): Milk adds moisture and richness to the cake batter. Whole milk is recommended for its higher fat content, which contributes to a more tender and flavorful cake. However, 2% milk will also work well. For a dairy-free option, you can use almond milk, soy milk, or oat milk, but be aware that these may slightly alter the flavor and texture of the cake.
• 1/2 cup Sour Cream (120 ml), (or plain Greek yogurt): Sour cream is the secret ingredient for that extra moist and fudgy texture! It also adds a subtle tang that balances the sweetness of the cake. Plain Greek yogurt is a great substitute if you don’t have sour cream on hand. Full-fat Greek yogurt will provide the most similar richness and moisture.
• 3/4 cup Freshly Brewed Coffee (180 ml), (or boiling water): Hot coffee (or boiling water) is crucial for blooming the cocoa powder and intensifying the chocolate flavor. Don’t worry, you won’t taste coffee in the final cake; it simply enhances the chocolate. Use freshly brewed hot coffee for the best results. If you don’t have coffee, boiling water will work in a pinch, but coffee truly elevates the chocolate flavor.

Chocolate Frosting Ingredients

• 3/4 cup Unsalted Butter (168 grams), (softened): Butter is the base of our rich and creamy frosting. Unsalted butter allows you to control the salt level in the frosting. Make sure the butter is softened to room temperature (but not melted!) for a smooth and fluffy frosting. Take it out of the refrigerator about an hour before you plan to make the frosting.
• 3-4 cups Powdered Sugar (330-440 grams), (sifted): Powdered sugar, also known as confectioners’ sugar, provides sweetness and structure to the frosting. Sifting the powdered sugar is essential to remove any lumps and ensure a smooth, lump-free frosting. The amount of powdered sugar you use will depend on your desired frosting consistency and sweetness. Start with 3 cups and add more, 1/2 cup at a time, until you reach your perfect frosting texture.
• 1/2 cup Cocoa Powder (45 grams), (sifted): Just like in the cake, cocoa powder brings the intense chocolate flavor to the frosting. Use the same type of cocoa powder you used in the cake for flavor consistency. Sifting the cocoa powder is again important for a smooth frosting.
• 1 teaspoon Vanilla Extract: Vanilla extract enhances the chocolate flavor in the frosting and adds a touch of warmth. Use pure vanilla extract for the best flavor.
• 1/4 teaspoon Salt: Salt balances the sweetness of the frosting and enhances the chocolate flavor.
• 4-5 tablespoons Whipping Cream (60-75 ml), (or milk): Whipping cream (or milk) is used to adjust the consistency of the frosting. Start with 4 tablespoons and add more, 1 tablespoon at a time, until you reach your desired frosting texture. Whipping cream will create a slightly richer and fluffier frosting than milk.

Instructions

Let’s get to the fun part – baking this incredible chocolate sheet cake! Follow these step-by-step instructions for both the cake and the frosting.

Chocolate Sheet Cake Instructions

1. Preheat the Oven and Prepare the Pan: Preheat your oven to 350°F (175°C). This is the ideal temperature for baking this cake evenly without drying it out. Grease a 9×13 inch baking pan thoroughly with butter or cooking spray. Then, dust the pan with cocoa powder instead of flour. This prevents white flour marks on your dark chocolate cake and adds a little extra chocolate flavor to the edges. Alternatively, and highly recommended, line the pan with parchment paper, leaving an overhang on the sides. This makes removing the cake from the pan a breeze, especially if you plan to frost it outside of the pan or freeze the unfrosted cake. The overhang acts like handles to lift the cake out easily.
2. Combine Dry Ingredients: In a large bowl, whisk together the all-purpose flour, cocoa powder, granulated sugar, baking soda, baking powder, and salt. Whisking aerates the dry ingredients and ensures they are evenly distributed. If your cocoa powder is lumpy, be sure to sift it into the bowl to prevent clumps in your batter. This step sets the stage for a smooth and evenly textured cake.
3. Combine Wet Ingredients: In a separate large bowl, whisk together the vegetable oil, eggs, vanilla extract, milk, and sour cream. Whisk until the mixture is well combined and slightly emulsified. Using a separate bowl for wet ingredients ensures they are properly mixed before being added to the dry ingredients, which is key to preventing overmixing later.
4. Combine Wet and Dry Ingredients: Make a well in the center of the dry ingredients in the first bowl. Pour the wet ingredients into this well. Start by gently stirring the wet and dry ingredients together with a spatula or wooden spoon. I like to do a few stirs by hand first to prevent a cloud of flour from puffing up when you start mixing with a whisk. Then, switch to a wire whisk and continue whisking until the ingredients are about 75% combined. Don’t worry about getting it perfectly smooth at this stage.
5. Add Hot Coffee and Finish Mixing: This is the magic step! Pour the hot coffee (or boiling water) into the batter. Immediately whisk vigorously with the wire whisk until you no longer see any lumps or streaks of dry ingredients. The mixture will become quite thin and liquidy – don’t be alarmed, this is normal! Whisk until the batter is smooth and even, and the hot coffee is fully incorporated and not sitting on top. This usually takes about a minute of vigorous whisking. The hot coffee blooms the cocoa powder, intensifying the chocolate flavor and creating a beautifully moist cake.
6. Bake the Cake: Pour the batter into the prepared 9×13 inch pan. The batter will be thin, which is expected for a sheet cake. Bake in the preheated oven for about 35 minutes. Start checking for doneness around 30 minutes by inserting a toothpick into the center of the cake. If the toothpick comes out clean or with just a few moist crumbs attached, the cake is done. If it comes out with wet batter, bake for a few more minutes and check again. Baking time can vary slightly depending on your oven, so it’s always best to use a toothpick test. Be careful not to overbake the cake, as this can make it dry. It may take up to 40 minutes in some ovens, but start checking at 30 minutes to be safe.
7. Cool Completely: Once the cake is baked, remove it from the oven and let it cool completely in the pan on a wire rack. Allowing the cake to cool completely before frosting is crucial. If you frost a warm cake, the frosting will melt and slide right off. Cooling usually takes about 30 minutes to an hour, depending on room temperature. If you used parchment paper, you can lift the cooled cake out of the pan using the overhang and place it directly on the wire rack to cool faster.

Chocolate Frosting Instructions

1. Soften the Butter: In a large bowl (or the bowl of a stand mixer fitted with the paddle attachment), beat the softened butter until it is light and creamy. This usually takes about 2-3 minutes on medium speed. Softened butter is key to a smooth and fluffy frosting.
2. Add Powdered Sugar and Cocoa Powder (Start with 2 cups): Sift 2 cups of powdered sugar and the sifted cocoa powder into the bowl with the softened butter. Also, add the vanilla extract and salt. Start mixing with the mixer on low speed to prevent the powdered sugar from flying everywhere. Gradually increase the speed to medium and beat until the ingredients are just combined.
3. Gradually Add Remaining Powdered Sugar and Cream: Add the remaining powdered sugar, about 1/2 cup at a time, alternating with 1-2 tablespoons of whipping cream (or milk). Continue beating on medium speed after each addition until the frosting reaches your desired consistency and sweetness. You may not need to use all 4 cups of powdered sugar; start with 3 cups and add more as needed. If the frosting becomes too thick, add a little more cream (or milk), 1 tablespoon at a time, until it thins out to your liking. If it’s too thin, add a bit more powdered sugar.
4. Frost the Cake: Once the cake is completely cooled, frost it generously with the chocolate frosting using a flat edge knife or an offset spatula. Spread the frosting evenly over the top of the cake. You can create swirls and peaks for a more decorative look, or keep it smooth and simple.
5. Decorate (Optional): If desired, decorate the frosted cake with sprinkles, chocolate shavings, chopped nuts, or any other toppings you like. Sprinkles add a festive touch, especially for celebrations!

Nutrition Facts

(Please note: Nutritional information is an estimate and can vary based on specific ingredients and serving sizes.)

• Servings: Approximately 18 slices
• Calories per serving (estimated): 350-450 calories (This is an estimate and will depend on frosting thickness and serving size. It’s best to use a nutrition calculator app if precise values are needed.)

Approximate Breakdown per Serving:

• Fat: 15-20g
• Saturated Fat: 8-12g
• Cholesterol: 50-70mg
• Sodium: 200-300mg
• Carbohydrates: 50-60g
• Sugar: 35-45g
• Protein: 3-4g

Preparation Time

• Prep Time: 25 minutes
• Cook Time: 35 minutes
• Cooling Time: 30 minutes
• Total Time: 1 hour 30 minutes

How to Serve

This chocolate sheet cake is incredibly versatile and can be served in so many delicious ways! Here are a few ideas:

• Classic Slice: The simplest and most satisfying way to enjoy this cake is just as a classic slice, frosted and ready to go. Perfect for any occasion!
• Warm with Ice Cream: For an extra decadent dessert, serve a warm slice of chocolate sheet cake with a scoop of vanilla ice cream or your favorite flavor. The warm cake and cold ice cream create a delightful contrast. A drizzle of chocolate sauce or caramel sauce would also be amazing.
• With Fresh Berries: The richness of the chocolate cake is beautifully balanced by the tartness of fresh berries. Serve slices of cake with a side of fresh raspberries, strawberries, or blueberries. A dollop of whipped cream alongside berries would elevate this even further.
• Coffee or Tea Pairing: Chocolate cake and coffee are a match made in heaven! Enjoy a slice of this cake with a cup of hot coffee or tea for a perfect afternoon treat or after-dinner dessert.
• Party Cake: Sheet cakes are ideal for parties and gatherings because they are easy to slice and serve to a crowd. This chocolate sheet cake is perfect for birthdays, potlucks, picnics, and any celebration. Decorate it with colorful sprinkles or themed decorations for a festive touch.
• Brownie-Style Squares: Cut the cooled cake into smaller squares for a brownie-like treat. These are perfect for lunchboxes, snacks, or a dessert buffet.
• Layered Dessert: Crumble leftover chocolate sheet cake and layer it in a trifle dish or individual cups with chocolate pudding, whipped cream, and chocolate shavings for a decadent layered dessert.

Additional Tips for Baking Success

1. Measure Ingredients Accurately: Baking is a science, and accurate measurements are crucial for success, especially with leavening agents like baking soda and baking powder. Use measuring cups and spoons specifically designed for baking. For dry ingredients like flour and sugar, spoon them into the measuring cup and level off the excess with a straight edge. For liquids, use liquid measuring cups and measure at eye level.
2. Room Temperature Ingredients: While not strictly necessary for all ingredients in this recipe, bringing your eggs and dairy (milk, sour cream) to room temperature can improve the batter’s emulsion and result in a smoother, more tender cake. Room temperature ingredients combine more easily and create a more homogenous batter.
3. Don’t Overmix the Batter: Overmixing can develop the gluten in the flour, leading to a tough cake. Mix the batter just until the ingredients are combined and no streaks of dry ingredients remain. Once you add the hot coffee, whisk vigorously to ensure everything is incorporated, but avoid excessive mixing after that point.
4. Cool Cake Completely Before Frosting: Patience is key! Make sure the cake is completely cooled before frosting. Frosting a warm cake will cause the frosting to melt and become runny, making it difficult to frost smoothly. If you’re in a hurry, you can speed up the cooling process by placing the cake in the refrigerator for a short time, but ensure it’s fully cooled before frosting.
5. Adjust Frosting Consistency: Frosting consistency is a personal preference. If you prefer a thicker frosting, add more powdered sugar, 1/2 cup at a time. If you prefer a thinner, more spreadable frosting, add more whipping cream or milk, 1 tablespoon at a time. Taste and adjust as you go until you reach your perfect frosting texture and sweetness.

Frequently Asked Questions (FAQ)

Q1: Can I use unsweetened applesauce instead of oil to make it healthier?

While you can substitute applesauce for oil in some baking recipes to reduce fat, it can significantly alter the texture of this cake, potentially making it denser and less moist. The oil is crucial for the fudgy texture of this sheet cake. For a healthier approach, consider reducing the amount of sugar slightly or focusing on portion control rather than drastically changing the fat content.

Q2: Can I make this cake ahead of time?

Absolutely! This chocolate sheet cake is a great make-ahead dessert. You can bake the cake a day or two in advance, let it cool completely, wrap it tightly in plastic wrap, and store it at room temperature. Frost it just before serving for the freshest flavor. You can also freeze the unfrosted cake for up to 2-3 months. Wrap it tightly in plastic wrap and then in foil before freezing. Thaw completely at room temperature before frosting.

Q3: I don’t have sour cream, can I use something else?

Yes, plain Greek yogurt is an excellent substitute for sour cream in this recipe. It provides a similar tang and moisture. Full-fat Greek yogurt will be the closest in richness to sour cream. You can also use buttermilk in a pinch, although it might slightly alter the texture.

Q4: Can I double the recipe to make a larger cake?

Yes, you can easily double this recipe to bake in a larger pan, such as a 12×18 inch sheet pan. Double all ingredients and bake for a slightly longer time, checking for doneness with a toothpick. Keep in mind that baking time will increase, so start checking around 40-45 minutes and adjust as needed.

Q5: My frosting is too thick/too thin, how can I fix it?

If your frosting is too thick, add more whipping cream or milk, 1 tablespoon at a time, and beat until you reach your desired consistency. If it’s too thin, add more powdered sugar, 1/4 to 1/2 cup at a time, and beat until it thickens up. Remember to add liquids or solids gradually to avoid over-adjusting and ending up with frosting that is too thin or too thick again!

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