Description
This French Onion Scalloped Potatoes recipe combines sweet caramelized onions, thinly sliced russet potatoes, and a creamy gruyere cheese sauce baked to golden perfection. It’s a comforting, savory dish perfect for family dinners or holiday gatherings.
Ingredients
Units
Scale
For the Onions
- 4 sweet onions, thinly sliced
- 4 tablespoons unsalted butter
- Kosher salt and pepper, to taste
- 1/2 teaspoon dried thyme
For the Potatoes
- 3 pounds russet potatoes, peeled
For the Sauce
- 4 tablespoons unsalted butter
- 4 tablespoons all-purpose flour
- 3 1/2 cups milk
- Kosher salt and pepper, to taste
- 1/4 teaspoon freshly grated nutmeg
- 12 ounces freshly grated gruyere cheese (divided)
Topping
- 1/3 cup seasoned bread crumbs
Instructions
- Caramelize the Onions: Preheat your oven to 375°F. Thinly slice the onions. Heat 4 tablespoons of butter in a skillet over medium heat. Add the onions with a large pinch of salt and pepper. Stir and cook for about 10 minutes, stirring occasionally until the onions begin to soften. Reduce heat to medium-low, stir in the dried thyme, and continue to cook for 30 to 40 minutes until the onions are golden and caramelized, stirring often. If the onions start to burn, lower the heat or add a splash of water; raise heat slightly if they are not cooking sufficiently.
- Prepare the Potatoes: Using a mandoline or sharp knife, slice the peeled russet potatoes very thinly to about ⅛ inch thickness or thinner. To prevent browning, place sliced potatoes in a bowl of ice water if preparing ahead or before assembling the dish.
- Make the Cheese Sauce: In a saucepan, melt the remaining 4 tablespoons of butter over medium heat. Whisk in the flour to form a roux and cook for 2 to 3 minutes until it turns golden and emits a nutty aroma. Slowly pour in the milk while whisking continuously to avoid lumps. Season with salt, pepper, and freshly grated nutmeg. Reduce heat to low, then gradually stir in half of the grated gruyere cheese until melted and smooth. Taste and adjust seasoning as needed.
- Assemble the Dish: In a baking dish, layer half of the sliced potatoes evenly. Spoon half of the cheese sauce over the potatoes, then spread half of the caramelized onions and half of the remaining grated gruyere on top. Add the remaining potatoes in a layer, followed by the rest of the cheese sauce, caramelized onions, and grated gruyere cheese. Finally, sprinkle the seasoned breadcrumbs evenly over the top.
- Bake: Bake the assembled dish uncovered in the preheated oven for 45 to 60 minutes, or until the potatoes are tender and can be pierced easily with a fork. If the top browns too much before the potatoes cook through, tent the dish loosely with foil. Allow to cool slightly before serving to let the sauce set.
Notes
- Use a mandoline for uniformly thin potato slices to ensure even cooking.
- Caramelizing onions takes patience but adds great depth of flavor; don’t rush the process.
- If onions start to stick or brown too quickly, add a splash of water to prevent burning.
- You can prepare the sliced potatoes in advance and store in ice water to prevent discoloration.
- Gruyere cheese can be substituted with Swiss or Emmental for a similar flavor profile.
- Cover the dish with foil if the topping browns too fast during baking to avoid burning.
- Let the scalloped potatoes rest for 10-15 minutes after baking to firm up before serving.
Nutrition
- Serving Size: 1 cup (about 1/10th of the recipe)
- Calories: 320
- Sugar: 6 g
- Sodium: 320 mg
- Fat: 15 g
- Saturated Fat: 9 g
- Unsaturated Fat: 5 g
- Trans Fat: 0 g
- Carbohydrates: 35 g
- Fiber: 3 g
- Protein: 10 g
- Cholesterol: 45 mg
