If you’re craving a soul-comforting dish that feels a little fancy but is totally doable, this French Onion Scalloped Potatoes Recipe is going to be your new best friend. Imagine tender, thinly sliced russet potatoes layered with sweet, deeply caramelized onions in a luscious gruyere cheese sauce—baked until bubbly and golden on top. Trust me, once you taste this, it’ll become your go-to for family dinners and special occasions alike. Let me walk you through every step to make sure your scalloped potatoes come out absolute perfection.
Why You’ll Love This Recipe
- Rich, Comforting Flavor: The caramelized onions bring a deep sweetness that perfectly complements creamy cheese and tender potatoes.
- Perfect for Gatherings: This recipe easily serves a crowd and looks stunning on the table.
- Make-Ahead Friendly: You can prep it ahead and bake when ready, making dinner effortless on busy days.
- A Classic with a Twist: Sweet onions and nutmeg in the sauce add a unique depth that elevates this beyond typical scalloped potatoes.
Ingredients & Why They Work
The magic of this French Onion Scalloped Potatoes Recipe lies in simple, high-quality ingredients combined in thoughtful ways. The sweet onions slowly caramelize to bring mellow richness, while russet potatoes provide the perfect starchy canvas with their creamy texture. Gruyere cheese adds a nutty, melty decadence, and a subtle touch of nutmeg in the sauce really rounds out the flavors. Make sure to pick firm potatoes and fresh cheese for best results!
- Sweet Onions: Their natural sweetness caramelizes beautifully, making the dish flavorful without bitterness.
- Unsalted Butter: Essential for control over seasoning and enriching both the onions and cheese sauce.
- Kosher Salt and Pepper: Simple seasonings that allow the main ingredients to shine while balancing flavors.
- Dried Thyme: Adds an earthy herbal note that complements the caramelized onions superbly.
- Russet Potatoes: Their starchy nature absorbs the cheese sauce well, resulting in tender, creamy layers.
- All-Purpose Flour: Used to create the roux that thickens the cream sauce perfectly.
- Milk: The base of the sauce—whole or 2% milk works best for creaminess without heaviness.
- Freshly Grated Nutmeg: Just a pinch elevates the sauce with warmth and subtle spice.
- Gruyere Cheese: Its nutty, creamy melt is key to the rich, decadent sauce and topping.
- Seasoned Bread Crumbs: Create a delightful crunchy topping for texture contrast.
Note: Exact ingredients and measurements are listed in the recipe card below.
Make It Your Way
One of the best parts about this French Onion Scalloped Potatoes Recipe is how easy it is to make your own. I often switch up the cheese based on what I have—sometimes I use a combo of gruyere and sharp white cheddar for a bit of tang. Feel free to adjust herbs or add garlic for extra punch. The layering can also be adapted to fit a smaller dish or individual ramekins for a fun presentation vibe.
- Variation: I once added a sprinkle of fresh rosemary along with thyme—my family loved the aromatic twist that gave a cozy forest flavor.
- Dairy-Free Option: Use a plant-based milk and vegan butter, and swap gruyere for your favorite melty vegan cheese. You’ll still get creamy, comforting layers.
- Make It Spicy: Add a pinch of cayenne or smoked paprika to the sauce for a little kick—perfect for those who like heat.
- Smaller Portions: This recipe scales down nicely for two or four people. Just keep those thin potato slices consistent for even baking.
Step-by-Step: How I Make French Onion Scalloped Potatoes Recipe
Step 1: Caramelize the Onions Slowly
Start by thinly slicing your sweet onions—this is key for even cooking. Melt your butter in a skillet on medium heat, then toss in the onions with a generous pinch of salt and pepper. Don’t rush this step. Stir occasionally, letting the onions soften over 10 minutes, then lower heat to medium-low. Add dried thyme and keep stirring every few minutes for about 30–40 minutes, until the onions turn golden and deeply caramelized. If they start sticking or burning, splash a bit of water or turn down the heat. Patience here pays off big time with flavor.
Step 2: Slice the Potatoes Thinly and Evenly
For that perfectly creamy texture, slice your peeled russet potatoes super thin—about an eighth of an inch or less. I love using a mandoline to keep things even, but be careful with your fingers! If you slice ahead of time, soak the slices briefly in ice water to stop browning and remove excess starch. Drain and dry thoroughly before layering.
Step 3: Make the Rich Gruyere Sauce
Next, melt butter in a saucepan and whisk in the flour to create a roux. Cook it until golden and smelling nutty—about 2 to 3 minutes. Slowly whisk in milk, a little at a time, until smooth and thickened. Lower heat, add salt, pepper, and that magic pinch of freshly grated nutmeg. Stir in half your grated gruyere until melty and silky. Taste and adjust seasoning—this sauce is what pulls the whole dish together.
Step 4: Layer and Bake to Golden Perfection
In a buttered baking dish, layer half the sliced potatoes, then half of your creamy cheese sauce. Spread half the caramelized onions over that, followed by half the remaining grated gruyere. Repeat with the remaining potatoes, sauce, onions, and cheese. Finish the dish by sprinkling the seasoned bread crumbs for a crunchy golden crust. Bake uncovered at 375°F for 45 to 60 minutes, or until the potatoes are tender and the top is beautifully golden. If the topping browns too fast, tent with foil to avoid burning.
Pro Tips for Making French Onion Scalloped Potatoes Recipe
- Caramelize Low and Slow: Don’t rush the onions! Slow cooking brings out the sweetness and prevents bitterness.
- Uniform Potato Slices: Use a mandoline or very sharp knife—uneven slices cause uneven baking.
- Season Layers Lightly: Salt each layer moderately to keep flavors balanced throughout the casserole.
- Let It Rest Before Serving: Giving it 10–15 minutes to cool helps the layers set and makes it easier to serve.
How to Serve French Onion Scalloped Potatoes Recipe
Garnishes
I love finishing this dish with a sprinkle of fresh thyme leaves or a little fresh chives chopped on top—it adds a pop of color and a fresh herbal note that cuts the richness. A tiny drizzle of good olive oil or a crack of fresh black pepper also adds a nice finishing touch.
Side Dishes
This recipe pairs brilliantly with roasted chicken, grilled steak, or even a fresh green salad to balance the creaminess. For holiday dinners, I serve it alongside steamed green beans and a bright, tangy cranberry sauce to brighten the plate.
Creative Ways to Present
For special occasions, I’ve baked individual portions in smallramekins topped with breadcrumbs and extra cheese—everyone loves having their own personal, bubbling, golden dish. You could also sprinkle toasted nuts like hazelnuts on top for a crunchy surprise, or make a gratin tower by stacking it vertically for a striking presentation.
Make Ahead and Storage
Storing Leftovers
After dinner, cover the scalloped potatoes tightly with foil or plastic wrap and refrigerate—they stay delicious for up to 3 days. When I reheat, I prefer slicing a portion and warming it up in the oven to keep that crispy top intact.
Freezing
French Onion Scalloped Potatoes freeze well if you want to prep ahead. I usually freeze it right after assembling (before baking). Wrap the dish tightly with foil and plastic wrap for extra protection. When ready, bake from frozen—just add 15-20 minutes to the baking time and cover with foil to prevent over-browning.
Reheating
To reheat leftovers, I pop them in a 350°F oven for about 20-30 minutes until warmed through. Cover with foil if you want to keep the top from burning but uncover near the end to refresh that crunchy breadcrumb topping.
FAQs
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Can I use yellow or white onions instead of sweet onions?
Yes, you can! However, sweet onions caramelize more easily and offer a milder, sweeter flavor that really complements the dish. Yellow onions work fine in a pinch but may yield a slightly sharper taste.
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Do I have to peel the potatoes?
Peeling the russet potatoes gives a smoother texture and appearance, making the layers creamier. If you prefer a more rustic dish, you can leave the skins on, but slice them very thinly to ensure they cook through.
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What can I substitute for Gruyere cheese?
Gruyere adds that nutty flavor and great melt, but if you can’t find it, Swiss cheese or a mild white cheddar can be good alternatives. Just avoid very sharp cheeses as they can overpower the delicate flavors.
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How long can I assemble ahead before baking?
You can assemble the dish and refrigerate for up to 24 hours before baking. Just cover it tightly with plastic wrap to prevent drying out.
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Is there a way to speed up the onion caramelization?
Caramelizing onions quickly can be tricky because the slow cooking brings out their best flavor. You can raise the heat a bit, but watch closely and stir often to avoid burning. Adding a small splash of water helps if they stick.
Final Thoughts
This French Onion Scalloped Potatoes Recipe holds a special place in my kitchen because it turns everyday ingredients into a luscious, comforting masterpiece. It’s a dish you make when you want to cozy up with loved ones or impress guests without stress. I hope you give it a try—it’s incredibly satisfying to pull that bubbling, golden casserole from the oven and watch everyone’s faces light up. Once you master these layers of creamy potatoes and sweet onions, you might just find yourself making it again and again!
PrintFrench Onion Scalloped Potatoes Recipe
This French Onion Scalloped Potatoes recipe combines sweet caramelized onions with thinly sliced russet potatoes baked in a rich Gruyère cheese sauce, topped with seasoned bread crumbs for a golden, crispy finish. Perfect as a comforting side dish for any occasion.
- Prep Time: 1 hour
- Cook Time: 1 hour
- Total Time: 2 hours
- Yield: 12 servings
- Category: Side Dish
- Method: Baking
- Cuisine: French
- Diet: Vegetarian
Ingredients
Onions and Potatoes
- 4 sweet onions, thinly sliced
- 4 tablespoons unsalted butter
- kosher salt and pepper, to taste
- 1/2 teaspoon dried thyme
- 3 pounds russet potatoes, peeled and thinly sliced
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 Gruyère cheese, divided
- 1/3 cup seasoned bread crumbs
Instructions
- Preheat Oven: Preheat the oven to 375 degrees Fahrenheit to prepare for baking.
- Caramelize Onions: Heat 4 tablespoons of butter in a skillet over medium heat. Add the thinly sliced onions with a big pinch of salt and pepper. Cook for 10 minutes, stirring occasionally to soften. Reduce heat to medium-low, add dried thyme, and continue cooking for 30 to 40 minutes, stirring often until onions are golden and caramelized. Adjust heat or add water to prevent burning.
- Slice Potatoes: Use a mandoline or sharp knife to thinly and uniformly slice potatoes about ⅛ inch thick or thinner. To avoid browning, soak slices in ice water if not assembling immediately.
- Make Cheese Sauce: Melt remaining 4 tablespoons butter in a saucepan over medium heat. Whisk in the flour to form a roux and cook for 2 to 3 minutes until golden and fragrant. Slowly whisk in milk, stirring constantly. Add salt, pepper, and grated nutmeg. Reduce heat to low and stir in half of the Gruyère cheese until melted. Adjust seasoning to taste.
- Assemble Layers: Spread half of the potato slices evenly in a baking dish. Top with half the cheese sauce, then half the caramelized onions, and half of the remaining Gruyère. Repeat layers with remaining potatoes, cheese sauce, caramelized onions, and Gruyère. Sprinkle seasoned bread crumbs on top.
- Bake: Bake uncovered for 60 minutes or until potatoes are tender and easily pierced with a fork. If the top browns too quickly, tent with foil to prevent burning.
- Rest and Serve: Let the dish cool slightly before serving to allow the sauce to set and flavors to meld.
Notes
- Using a mandoline ensures thin, uniform potato slices for even cooking.
- Soaking potato slices in ice water prevents discoloration before baking.
- Adjust salt and pepper at various stages for balanced flavor.
- If Gruyère cheese is unavailable, Swiss cheese can be used as a substitute.
- To keep the top from burning, cover loosely with foil during the last 10-15 minutes of baking if necessary.
