Cheesy Scalloped Potatoes
Cheesy Scalloped Potatoes combine thinly sliced russet potatoes and sweet onions layered and baked in a creamy, cheesy sauce until tender and bubbly. The dish finishes with a golden broiled top for extra crispness. This rich and comforting side is perfect alongside roasts, poultry, or as a satisfying vegetarian option.
Equipment
- Medium saucepan (1)
- Mandoline slicer (optional) (1)
- 8×8-inch glass baking dish (1)
- Whisk (1)
- Aluminum foil (1 sheet)
Ingredients
- 4 medium russet potatoes peeled and thinly sliced (about 2 pounds)
- 1 large yellow onion sliced into rings
- 3 tablespoons unsalted butter
- 3 tablespoons all-purpose flour
- ½ teaspoon kosher salt plus more to taste
- 2 cups whole milk at room temperature
- 1½ cups mild cheddar cheese shredded
- Freshly ground black pepper to taste
- Nonstick cooking spray for greasing
Instructions
- Prepare the Oven and Dish: Preheat your oven to 400°F (200°C). Lightly grease an 8×8-inch baking dish with nonstick spray to prevent sticking and help with easy cleanup.
- Slice and Layer Potatoes and Onions: Peel the potatoes and cut them into uniform ¼-inch slices. Slice the onion into thin rings. Arrange the potato slices in the baking dish, overlapping slightly, then layer the onion rings on top. Continue alternating layers of potatoes and onions until all are used, creating a visually appealing stack.
- Make the Creamy Cheese Sauce: In a medium saucepan, melt the butter over medium heat. Once melted, whisk in the flour and salt, stirring continuously for about one minute to form a smooth roux without any lumps. Gradually add the room-temperature milk while whisking constantly. Cook the mixture until it thickens enough to coat the back of a spoon, about 3-5 minutes. Remove from heat and stir in the shredded cheddar cheese until completely melted and the sauce is smooth.
- Combine and Cover: Pour the rich cheese sauce evenly over the layered potatoes and onions, making sure every slice is coated. Cover the baking dish tightly with aluminum foil to trap steam, which helps soften the potatoes during baking.
- Bake Until Tender: Place the covered dish in the preheated oven and bake for approximately 85-90 minutes. The potatoes should be fork-tender and fully cooked through.
- Optional Crisp Topping: For a golden, bubbly finish, remove the foil and switch your oven to broil. Broil the scalloped potatoes for 2-4 minutes, keeping a close eye to avoid burning, until the top turns beautifully golden brown.
- Season and Serve: Remove from the oven and season with additional salt and freshly ground black pepper to taste. Let the dish rest for a few minutes before serving to allow the sauce to thicken slightly.
Notes
- Uniform Slices: For even cooking, try to slice potatoes and onions evenly. Using a mandoline slicer can save time and ensure consistent thickness.
- Cheese Variations: Mild cheddar works beautifully here, but feel free to experiment with sharp cheddar, Gruyère, or a blend for different flavor profiles.
- Make-Ahead Tip: You can prepare the layers and sauce ahead of time, refrigerate covered, and bake when ready—just add extra baking time if starting cold.
- Dairy Alternatives: For a lighter version, substitute whole milk with 2% or use a plant-based milk (unsweetened almond or oat milk) though the texture may vary slightly.
- Leftovers: Store leftovers in an airtight container in the fridge for up to 3 days. Reheat gently in the oven or microwave.
