Ingredients
- Potatoes: 2.5 – 3 lbs (about 8-10 medium) Yukon Gold or Russet potatoes, peeled and thinly sliced (about 1/8-inch thick)
- Unsalted Butter: 4 tablespoons, plus more for greasing the dish
- All-Purpose Flour: 1/4 cup
- Whole Milk: 2 cups, warmed
- Heavy Cream: 1 cup, warmed
- Yellow Onion: 1 small, finely minced or grated (about 1/2 cup)
- Garlic: 2-3 cloves, minced
- Cheese: 2 cups shredded sharp cheddar cheese (or a blend of cheddar and Gruyère for extra flavor)
- Salt: 1 ½ teaspoons (or to taste)
- Freshly Ground Black Pepper: ½ teaspoon (or to taste)
- Nutmeg: ¼ teaspoon, freshly grated (optional, but adds a classic touch)
- Fresh Thyme or Parsley: 1 tablespoon, chopped (for garnish, optional)
Instructions
- Preheat and Prepare:
- Preheat your oven to 375°F (190°C).
- Generously grease a 9×13 inch baking dish with butter. Set aside.
- Slice the Potatoes:
- Peel the potatoes. Using a mandoline slicer (highly recommended for uniform thickness) or a very sharp knife, slice the potatoes into 1/8-inch thick rounds. Uniformity is key for even cooking.
- As you slice the potatoes, you can place them in a bowl of cold water to prevent browning if you’re not immediately ready to assemble. However, if assembling right away, avoid rinsing, as the surface starch helps thicken the sauce. If you do soak them, pat them thoroughly dry with paper towels before layering.
- Sauté Aromatics:
- In a medium saucepan or Dutch oven, melt 4 tablespoons of butter over medium heat.
- Add the finely minced onion and cook, stirring occasionally, until softened and translucent, about 5-7 minutes. Don’t let it brown.
- Add the minced garlic and cook for another 1-2 minutes until fragrant.
- Create the Roux and Sauce:
- Sprinkle the all-purpose flour over the softened onions and garlic. Cook, stirring constantly with a whisk, for 1-2 minutes. This cooks out the raw flour taste and forms a roux, which will thicken your sauce.
- Gradually whisk in the warmed whole milk and heavy cream. Start with a small amount of liquid, whisking vigorously to create a smooth paste, then continue adding the remaining liquid slowly, whisking continuously to prevent lumps.
- Bring the sauce to a gentle simmer, stirring frequently. Cook for 3-5 minutes, or until the sauce has thickened enough to coat the back of a spoon.
- Remove the saucepan from the heat. Stir in the salt, freshly ground black pepper, and freshly grated nutmeg (if using).
- Stir in 1 cup of the shredded cheese until melted and the sauce is smooth. Taste and adjust seasoning if necessary. Remember that the potatoes will absorb some salt.
- Assemble the Scalloped Potatoes:
- Arrange one-third of the sliced potatoes in an even layer in the bottom of the prepared baking dish, slightly overlapping the slices.
- Pour about one-third of the creamy cheese sauce over the potato layer, spreading it evenly.
- Sprinkle with about 1/3 cup of the remaining shredded cheese.
- Repeat with another layer of potatoes, another third of the sauce, and another 1/3 cup of cheese.
- Finish with the final layer of potatoes, the remaining sauce, and top generously with the last 1/3 cup (or a bit more if you love cheese!) of shredded cheese. Ensure the top layer of potatoes is well-coated with sauce to prevent them from drying out.
- Bake to Golden Perfection:
- Cover the baking dish tightly with aluminum foil. This helps steam the potatoes and cook them through without the top browning too quickly.
- Bake in the preheated oven for 45 minutes.
- After 45 minutes, carefully remove the aluminum foil.
- Continue baking, uncovered, for another 20-30 minutes, or until the potatoes are tender when pierced with a fork, the sauce is bubbly, and the top is beautifully golden brown and slightly crispy in places. If the top starts to brown too quickly, you can loosely tent it with foil again.
- Rest Before Serving:
- Once baked, remove the scalloped potatoes from the oven and let them rest for at least 10-15 minutes before serving. This crucial step allows the sauce to thicken further and set, making it easier to serve neat portions and preventing the potatoes from being too molten hot.
- Garnish with fresh chopped thyme or parsley before serving, if desired.
Nutrition
- Serving Size: One Normal Portion
- Calories: 400-450