For the Coffee Cake:

• 1/2 cup Salted Butter, Softened: Butter is the heart of any good cake, and in this gluten-free version, it’s no different. Using salted butter not only adds richness and flavor but also contributes to the tender crumb of the cake. Softened butter is absolutely key here. It needs to be at room temperature, pliable enough to easily cream with sugar, but not melted. This creamy texture is essential for incorporating air into the batter, which results in a light and fluffy cake. If your butter is too cold, it won’t cream properly, and if it’s too melted, the cake can become greasy. Using high-quality butter will also significantly enhance the overall flavor of your coffee cake, so opting for a good brand is always a worthwhile investment. For those who prefer unsalted butter, simply add a pinch of salt (about 1/4 teaspoon) to the dry ingredients to balance the sweetness.
• 2/3 cup Applesauce: Applesauce is a secret weapon in gluten-free baking. It adds moisture and tenderness to the cake without adding extra fat. In this recipe, it works alongside the butter to create a moist and buttery texture that’s simply irresistible. Unsweetened applesauce is preferred so that you can control the sweetness of the cake. It also acts as a binder, helping to hold the gluten-free flours together. You can use store-bought applesauce, but homemade applesauce, if you have the time, can add an even more nuanced flavor to your cake. The natural pectin in applesauce also contributes to the cake’s structure, giving it a pleasant chewiness.
• 2 Eggs: Eggs are another vital ingredient in baking, providing structure, richness, and moisture. In this gluten-free coffee cake, they act as a binder, holding together the almond and oat flours, and contributing to the cake’s overall texture. Using large eggs at room temperature is recommended for best results. Room temperature eggs emulsify more easily into the batter, creating a smoother and more homogenous mixture. This better emulsion leads to a more tender and evenly baked cake. Eggs also add a subtle richness and enhance the overall flavor profile of the coffee cake.
• 1 cup White Sugar: Sugar not only adds sweetness but also contributes to the moisture and tenderness of the cake. White sugar, also known as granulated sugar, is used here for its clean sweetness and its ability to cream well with butter. The creaming process, where sugar is beaten with softened butter, is crucial for incorporating air into the batter, resulting in a lighter and fluffier cake. If you prefer a slightly less sweet cake, you can reduce the sugar by a tablespoon or two, but be mindful that sugar also contributes to the cake’s structure and moisture balance.
• 2 tsp Vanilla Extract: Vanilla extract is a flavor enhancer, adding a warm and aromatic note that complements the cinnamon and buttery flavors of the coffee cake beautifully. Using pure vanilla extract is always recommended for the best flavor. Imitation vanilla extract can sometimes taste artificial and doesn’t provide the same depth of flavor. A good quality vanilla extract will elevate the overall taste of your coffee cake, making it even more delicious and inviting. You can also experiment with vanilla bean paste for an even more intense vanilla flavor, using about 1 teaspoon of paste as a substitute for the extract.
• 1 cup Almond Flour: Almond flour is a star ingredient in gluten-free baking, adding a slightly nutty flavor and a wonderfully moist and tender texture to baked goods. It’s made from blanched almonds that have been finely ground. Almond flour is naturally gluten-free and is a good source of healthy fats and protein. In this recipe, it provides structure and a delicate crumb, preventing the cake from becoming dry or crumbly, which can sometimes happen with gluten-free baked goods. It’s important to use finely ground almond flour for the best texture. Almond meal, which is made from almonds with their skins on and is coarser, is not recommended for this recipe as it can result in a grittier texture.
• 1 1/4 cup Oat Flour: Oat flour is another excellent gluten-free flour that adds a slightly sweet and wholesome flavor to the coffee cake. It also contributes to a soft and slightly chewy texture. Make sure to use certified gluten-free oat flour if you are strictly gluten-free, as regular oats can sometimes be cross-contaminated with gluten. Oat flour is readily available in most supermarkets, or you can easily make your own by grinding rolled oats in a food processor or high-speed blender until they reach a fine flour consistency. Oat flour is also a good source of fiber, adding a bit of nutritional value to your treat.
• 2 tsp Baking Powder: Baking powder is a chemical leavening agent that makes the coffee cake rise and become light and airy. It’s essential for achieving the desired fluffy texture. Make sure your baking powder is fresh, as it loses its potency over time. To check if your baking powder is still active, you can test a small amount by mixing it with hot water – it should bubble vigorously. Using the correct amount of baking powder is crucial; too little and the cake will be dense, too much and it might rise too quickly and then collapse.
• 1/4 tsp Salt: Salt is a flavor enhancer that might seem counterintuitive in a sweet recipe, but it’s crucial for balancing the sweetness and bringing out the other flavors. It enhances the buttery, cinnamon, and vanilla notes, creating a more complex and delicious overall flavor profile. Salt also helps to control the yeast in the baking powder and strengthens the gluten-free flour structure, contributing to a better texture.

For the Cinnamon Sugar Filling:

• 2 tbsp Salted Butter, Melted: Melted butter is used in the cinnamon sugar filling to bind the sugar and cinnamon together and create a moist and flavorful swirl throughout the cake. The melted butter also helps to create those beautiful, gooey pockets of cinnamon sugar that are so characteristic of coffee cake. Using salted butter here enhances the overall flavor and complements the sweetness of the sugar.
• 1 tbsp Oat Flour: A small amount of oat flour is added to the cinnamon sugar filling to help thicken it slightly and prevent it from sinking completely to the bottom of the cake. It also helps to create a slightly more cohesive swirl that is evenly distributed throughout the cake layers. If you don’t have oat flour readily available, you can substitute with a tablespoon of almond flour, though oat flour is preferred for its slightly finer texture in this application.
• 2 tbsp White Sugar: White sugar is used in the cinnamon sugar filling to add sweetness and create that classic cinnamon sugar flavor. It dissolves into the melted butter and oat flour, creating a delicious and slightly caramelized swirl as the cake bakes.
• 1/2 tbsp Cinnamon: Cinnamon is the star spice in this coffee cake, providing its signature warm and aromatic flavor. Using high-quality cinnamon will make a significant difference in the overall taste. Freshly ground cinnamon, if you have it, will have an even more intense and fragrant aroma. Adjust the amount of cinnamon to your preference – if you love cinnamon, you can increase it slightly to ¾ tablespoon, or reduce it to ¼ tablespoon if you prefer a milder cinnamon flavor.

For the Crumble Topping:

• 1/4 cup Salted Butter, Slightly Softened (Room Temperature): Slightly softened butter is used in the crumble topping to create those perfect, crumbly clusters. Unlike the butter for the cake batter, which needs to be fully softened and creamy, the butter for the crumble topping should still be slightly firm but pliable. This allows you to easily incorporate it into the dry ingredients to form crumbles. If the butter is too soft, the topping will become more like a paste rather than crumbles.
• 1/4 cup Light Brown Sugar: Light brown sugar adds sweetness and moisture to the crumble topping, as well as a hint of molasses flavor that complements the cinnamon and butter beautifully. The moisture in brown sugar helps to keep the topping from becoming too dry and adds a delightful chewiness to the crumbles. You can also use dark brown sugar for a richer molasses flavor, or granulated sugar if you prefer a less intense sweetness.
• 1/4 cup Almond Flour: Almond flour is used in the crumble topping to add structure and a slightly nutty flavor. It helps to create those distinct crumbles and prevents the topping from becoming too dense or sticky.
• 1/2 cup Oat Flour: Oat flour is the main flour component of the crumble topping, providing bulk and a slightly wholesome flavor. It contributes to the crumbly texture and helps to absorb some of the butter, creating those perfect clusters.
• 2 tsp Cinnamon: Cinnamon is added to the crumble topping to enhance the cinnamon flavor of the coffee cake and create a cohesive flavor profile throughout the entire treat. It complements the cinnamon in the filling and the cake itself, making for a truly cinnamon-lover’s delight. Again, using high-quality cinnamon will elevate the flavor of your crumble topping.