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Cheesy French Onion Scalloped Potatoes Recipe

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★★★★★

4.7 from 715 reviews

Cheesy French Onion Scalloped Potatoes is a comforting casserole dish featuring tender layers of thinly sliced Russet potatoes smothered in a rich, creamy cheese sauce made with mild cheddar and Gruyère cheese. Caramelized yellow onions add a deep, sweet flavor contrast, making this dish perfect as a hearty side or vegetarian main.

Ingredients

Scale

For the Onions

  • 2 large yellow onions, thinly sliced into rings
  • 2 tablespoons unsalted butter

For the Potatoes

  • 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

Instructions

  1. Melt butter and caramelize onions: In a large skillet over medium-low heat, melt 2 tablespoons of butter. Add the thinly sliced onions and cook, stirring frequently, until they become deeply golden and caramelized, about 30-45 minutes. Remove the skillet from heat and set the onions aside.
  2. Preheat oven and prepare casserole dish: Preheat your oven to 400°F (200°C). Lightly spray an 8×8-inch casserole dish with nonstick cooking spray and set aside.
  3. Make roux for cheese sauce: In a medium saucepan over medium heat, melt the remaining 2 tablespoons of butter. Whisk in the flour and ½ teaspoon kosher salt, cooking and whisking constantly for about 1 minute to form a roux.
  4. Add milk and thicken sauce: Slowly pour in the milk while whisking continuously to avoid lumps. Continue cooking and whisking frequently until the sauce thickens and begins to bubble, about 5-7 minutes.
  5. Incorporate cheese into sauce: Remove the sauce from heat and stir in ½ cup of shredded mild cheddar and ½ cup of shredded Gruyère cheese, reserving the remaining ¼ cup of each for the topping. Mix until smooth.
  6. Layer potatoes and cheese sauce: Arrange the sliced potatoes 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 the sauce seep between layers.
  7. Add caramelized onions and cheese topping: Spread the caramelized onions evenly over the cheesy potatoes. Sprinkle the reserved ¼ cup shredded cheddar and ¼ cup Gruyère cheese over the top.
  8. Bake covered: Cover the casserole dish tightly with aluminum foil and bake for 85-90 minutes, or until the potatoes are tender when pierced with a fork.
  9. Uncover and brown: Remove the foil and bake uncovered for the last 10 minutes to allow the top to brown.
  10. Optional broil for crisp top: For an extra golden and crispy top, place the casserole under the broiler for 2-4 minutes. Watch closely to prevent burning.
  11. Cool, season, and garnish: Let the dish cool for 5-10 minutes before serving. Season with salt to taste and garnish with chopped parsley.

Notes

  • Ensure the onions are deeply caramelized for the best flavor — this process can take up to 45 minutes on low heat.
  • Use room temperature milk to prevent lumps in the cheese sauce.
  • Russet potatoes work best for scalloped potatoes due to their starchy texture that becomes tender when baked.
  • Make sure to slice potatoes evenly for uniform cooking.
  • Watch carefully when broiling to avoid burning the cheese topping.
  • The dish can be prepared a day ahead, assembled and refrigerated, then baked before serving.

Keywords: scalloped potatoes, cheesy potatoes, french onion, caramelized onions, casserole, comfort food, vegetarian side dish

Find it online: https://todayfoodrecipe.com/cheesy-french-onion-scalloped-potatoes-recipe/