French Onion Scalloped Potatoes

5 from 1 vote

French Onion Scalloped Potatoes

Layers of tender Yukon Gold potatoes, caramelized onions, and melted Gruyère bring all the cozy flavor of French onion soup to this creamy potato side dish. Perfect for any holiday side.

Prep Time20

Cook Time2 15

Total Time2 45

Course: Side Dish

Cuisine: American, French

Keyword: Casserole, Comfort Food, Dinner, Holiday, Side Dish, The Cooking Mawma

Servings: people

Equipment

1 9x13 baking dish
1 Large skillet
Mandolin slicer optional

Ingredients

For the caramelized onions

3 tablespoons butter
1 tablespoon olive oil
3 large yellow onions thinly sliced
1 teaspoon kosher salt
½ teaspoon black pepper
1 teaspoon sugar
1 teaspoon garlic powder
1 teaspoon dried thyme
½ cup beef broth

For the potatoes

2 1/2 pounds Yukon Gold potatoes sliced into even ⅛-inch-thick rounds
1½ cups heavy cream
1 teaspoon kosher salt
¼ teaspoon black pepper
1 teaspoon fresh thyme leaves
1½ cups freshly shredded Gruyère cheese divided
Fresh thyme for serving optional

Instructions

Caramelize the onions. Heat the butter and olive oil in a large skillet over medium-low heat. Add the onions, salt, pepper, sugar, garlic powder and thyme and mix. Cook for 40–50 minutes, stirring occasionally, until deeply golden and soft. If the pan starts to dry out or the onions stick, add a splash of water.
Add the flavor. Pour in the beef broth, scraping up any browned bits. Simmer for 3–5 minutes, until most of the liquid has cooked off and the onions are jammy.
Prep the potatoes. Preheat the oven to 375°F. Grease a 9×13-inch baking dish with nonstick cooking spray. In a large bowl, toss the sliced potatoes with the heavy cream, salt, pepper, and fresh thyme.
Layer the casserole. Arrange half the potatoes in overlapping layers in the baking dish. Spread half the onions over them and sprinkle with half the Gruyère. Repeat with the remaining potatoes, onions, and cheese. Pour any cream left in the bowl evenly over the top.
Bake covered. Cover tightly with foil and bake for 50–60 minutes, until the potatoes are nearly tender when pierced with a knife. If they’re still firm, cover and continue baking before moving to the next step.
Brown the top. Remove the foil and bake for another 15–20 minutes, until the potatoes are fully tender and the top is golden and bubbly. For extra browning, broil for 1–2 minutes, watching closely.
Rest and serve. Let rest for 10–15 minutes so the cream can thicken slightly. Garnish with fresh thyme, if using, and serve warm.

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