Name: Cheesy French Onion Scalloped Potatoes Recipe
Prep time: 20 min
Cook time: PT-491832H44M48S
Total time: PT-491832H44M48S
Cuisine: French
Ingredients: 2 large yellow onions, thinly sliced into rings; 2 tablespoons unsalted butter; 4 Russet potatoes, about 2 pounds, peeled and sliced into ¼-inch thick rounds; 4 tablespoons unsalted butter, divided; 2 tablespoons all-purpose flour; ½ teaspoon kosher salt, plus more to taste; 1 ½ cups whole milk, room temperature; ¾ cup (85 g) mild cheddar cheese, shredded, divided; ¾ cup (85 g) Gruyère cheese, shredded, divided; Nonstick cooking spray; Parsley, chopped for garnish

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Introduction

Cheesy French Onion Scalloped Potatoes combine tender, thinly sliced potatoes with rich, caramelized onions and melted cheese for a comforting, flavorful side dish. It’s perfect for holidays, family dinners, or any time you’re craving something warm and satisfying.

A white oval baking dish holds a golden brown baked casserole, topped with caramelized onion layers that are glossy and dark amber in color scattered unevenly over a melted cheese layer with creamy white and light golden spots. Small green herb pieces are sprinkled lightly across the surface for a fresh touch, while the edges have a slightly crispy, browned texture. The dish sits on a white marbled texture partially covered by a soft brown cloth, with a small bowl of chopped green herbs on the side, adding a fresh contrast. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

4 tablespoons unsalted butter, divided
2 large yellow onions, thinly sliced into rings
4 Russet potatoes (about 2 pounds), peeled and sliced into ¼-inch thick rounds
2 tablespoons all-purpose flour
½ teaspoon kosher salt
1 ½ cups whole milk, room temperature
¾ cup (85 g) mild cheddar cheese, shredded, divided
¾ cup (85 g) Gruyère cheese, shredded, divided
Salt, to taste
Parsley, chopped for garnish

Instructions

Step 1: In a large skillet over medium-low heat, melt 2 tablespoons of the butter. Add the sliced onions and cook, stirring frequently, until they are deeply golden and caramelized, about 30-45 minutes. Set aside.
Step 2: Preheat the oven to 400°F. Lightly spray an 8×8-inch casserole dish with nonstick cooking spray and set aside.
Step 3: In a medium saucepan over medium heat, melt the remaining 2 tablespoons butter. Whisk in the flour and kosher salt, cooking constantly for 1 minute to form a roux.
Step 4: Slowly whisk in the milk, ensuring there are no lumps. Continue cooking, whisking frequently, until the sauce thickens and bubbles, about 5-7 minutes.
Step 5: Remove from heat and stir in ½ cup shredded cheddar and ½ cup Gruyère until smooth, reserving the remaining cheese for topping.
Step 6: Arrange the potato slices in an even, overlapping layer in the prepared casserole dish. Pour the cheese sauce evenly over the potatoes, gently tilting the dish or using a spatula to help it seep between layers.
Step 7: Spread the caramelized onions evenly over the cheesy potatoes. Then sprinkle the remaining ¼ cup cheddar and ¼ cup Gruyère on top.
Step 8: Cover the dish tightly with aluminum foil and bake for 85-90 minutes, or until the potatoes are tender when pierced with a fork.
Step 9: Remove the foil for the last 10 minutes to brown the top. For an extra golden, crisp top, broil for 2-4 minutes, watching closely to prevent burning.
Step 10: Let cool for 5-10 minutes before serving. Season with salt to taste and garnish with chopped parsley.

Tips & Variations

Use Yukon Gold potatoes for a creamier texture and slightly buttery flavor.
Swap Gruyère with Swiss cheese if you prefer a milder taste.
For extra flavor, add a teaspoon of fresh thyme or rosemary to the cheese sauce.
Make it ahead and refrigerate before baking; increase baking time slightly if baking from cold.

Storage

Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven at 350°F until warmed through to maintain the creamy texture. Avoid microwaving to prevent the dish from drying out.

How to Serve

A white oval baking dish filled with a creamy baked dish that has a golden brown top layer of melted cheese with crispy edges. The top is covered with caramelized onions that are slightly dark golden in color and scattered bits of green herbs. The dish sits on a wooden surface with a beige cloth partially underneath and a brown cloth nearby. A small dark bowl filled with chopped green herbs is visible in the background. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use a different type of cheese?

Yes, you can substitute Gruyère with Swiss or mozzarella for a less intense flavor. Cheddar can also be replaced with Monterey Jack or Colby for a smoother melt.

How do I know when the potatoes are done baking?

The potatoes are tender when a fork or knife easily pierces through them without resistance. If they feel firm, cover and bake a little longer, checking every 10 minutes.