French Onion Scalloped Potatoes
French Onion Scalloped Potatoes combine the rich flavors of caramelized onions and melted cheese with tender scalloped potatoes, creating a comforting and elegant side dish perfect for any occasion.
Servings: 6 servings
Ingredients
- 3 large yellow onions thinly sliced
- 2 tablespoons olive oil
- 2 cloves garlic minced
- 1 teaspoon fresh thyme leaves or ½ teaspoon dried thyme
- 4 tablespoons unsalted butter
- 4 tablespoons all-purpose flour
- 3 cups low-sodium beef broth or vegetable broth for lighter taste
- 2 cups whole milk or plant-based milk alternative
- 2 pounds Yukon Gold potatoes peeled and thinly sliced (about 1/8-inch thick)
- 1.5 cups shredded Gruyère cheese or substitute with mozzarella or mild cheddar
- Salt and freshly ground black pepper to taste
- Fresh parsley chopped (for garnish)
Instructions
- Heat olive oil in a large skillet over medium heat. Add the thinly sliced onions and a pinch of salt. Cook, stirring occasionally, for 25-30 minutes until the onions are deeply golden and caramelized. Add the minced garlic and thyme in the last 5 minutes of cooking, stirring to combine. Remove from heat and set aside.
- In a medium saucepan, melt the butter over medium heat. Whisk in the flour and cook for about 2 minutes, stirring constantly, until the mixture is bubbly and slightly golden. Slowly whisk in the beef broth and milk, ensuring no lumps form. Continue cooking and whisking until the sauce thickens, about 5-7 minutes. Season with salt and pepper to taste. Remove from heat and stir in half of the shredded cheese.
- Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish. Layer half of the sliced potatoes evenly in the dish. Spread half of the caramelized onions over the potatoes, then pour half of the creamy sauce on top. Repeat with the remaining potatoes, onions, and sauce.
- Sprinkle the remaining cheese evenly over the top of the casserole. Cover the dish with foil and bake for 45 minutes. Remove the foil and bake for an additional 20-25 minutes, or until the top is golden brown and the potatoes are tender when pierced with a fork.
- Allow the dish to cool for 10 minutes before serving. Garnish with chopped fresh parsley for a pop of color and fresh flavor.
Equipment
- Large Skillet
- Medium Saucepan
- 9x13-inch Baking Dish
- Oven
Notes
Slice potatoes evenly using a mandoline or sharp knife for uniform cooking. Cook onions low and slow for best caramelization. Gruyère cheese is classic but mozzarella or mild cheddar can be used. The dish can be assembled a day ahead and baked later (add 10 minutes to baking time if baking from fridge). Let the casserole rest before serving to help sauce thicken. Variations include using sweet potatoes, adding mushrooms, spicing with paprika or cayenne, making it vegan, or experimenting with herbs like rosemary or sage. Store leftovers in the refrigerator for up to 3 days and reheat covered in oven or microwave.