I’ve made this French Onion Potato Bake more times than I can count when I need a comforting, crowd-pleasing side that eats like a main. Thinly sliced potatoes layered with deeply caramelized onions, melting Gruyère, and a blanket of cream—this dish hits that cozy, savory rhythm that works for weeknight dinners, holiday spreads, or a simple Sunday supper.

If you love the idea of French onion flavors in other dishes, you might also enjoy this crock-pot French onion chicken for an easy weeknight protein: Crock-Pot French Onion Chicken.

Why you’ll love this dish

This recipe takes two humble stars—potatoes and onions—and turns them into something layered, silky, and rich without any fuss. It’s budget-friendly, feeds a crowd, and is forgiving: if your onions run a few minutes longer in the skillet or your slices aren’t perfectly even, the oven will still pull everything together.

Feeds a family or makes a showy side for guests.
Uses pantry basics with an upgrade from Gruyère or Swiss cheese.
Great for make-ahead comfort: bake and reheat, or assemble and refrigerate before cooking.

“Comfort food with depth: caramelized onions and melted Gruyère make this my go-to for potlucks.” — home cook review

The cooking process explained

Quick overview so you know what’s coming: caramelize the onions slowly until deeply browned and sweet, thinly slice the potatoes, layer potatoes, onions, and cheese, pour cream, then bake covered until tender. Uncover at the end to brown the top.

Expect about 15–20 minutes caramelizing time, 45 minutes covered baking, plus 15 minutes uncovered. Plan roughly 1 hour 15 minutes active-to-finish time, though active hands-on time is mostly the onions and assembly.

What you’ll need

4 large potatoes, thinly sliced (see notes below)
2 large onions, thinly sliced
2 cups shredded cheese (Gruyère or Swiss recommended)
1 cup heavy cream
2 tablespoons olive oil (or 1 tbsp oil + 1 tbsp butter)
Salt and pepper to taste
Fresh thyme (optional, for garnish)

Substitutions/notes: Yukon Golds hold their shape and have a buttery flavor; russets give a creamier texture. If you don’t have heavy cream, use 3/4 cup whole milk + 1/4 cup cream or 1 cup half-and-half (the bake will be slightly less rich). Use grated Emmental, Comté, or a mild cheddar if needed.

How to prepare it

Preheat the oven to 375°F (190°C).
Heat olive oil in a large skillet over medium heat. Add the thinly sliced onions with a pinch of salt. Cook, stirring occasionally, until deeply golden and caramelized — about 15–20 minutes. Lower heat if they start to brown too quickly.
Grease a 9×13-inch baking dish.
Layer half the potato slices in the dish in an even layer.
Spread half the caramelized onions over the potatoes, then sprinkle half the shredded cheese.
Repeat with the remaining potatoes, onions, and cheese.
Pour the heavy cream evenly over the top. Season with salt and plenty of black pepper.
Cover tightly with foil and bake for 45 minutes.
Remove the foil and bake another 15 minutes, or until the top is golden and bubbly and a knife slides easily into the center.
Let rest 5–10 minutes, garnish with fresh thyme if using, and serve warm.

How to serve

Best ways to enjoy it: Serve as a hearty side with roast chicken or pork, or pair with a crisp green salad for a lighter meal.
For a complete plate: add a simple pan-seared steak and a bright mustard vinaigrette on the side — if you like potato-and-steak combos, see this loaded steak and potato bake for inspiration: Crockpot Loaded Steak and Potato Bake.
For presentation: slice into squares, garnish with thyme sprigs, and place on warm plates to keep the cheese melty.

Storage and reheating tips

Refrigerate: Cool completely, cover tightly, and refrigerate up to 3–4 days.
Reheat: Warm individual portions in the microwave, or reheat the whole dish in a 350°F (175°C) oven for 15–20 minutes until heated through. Add a few minutes under the broiler if you want to re-crisp the top.
Freeze: Assemble (but don’t bake), wrap tightly, and freeze up to 2 months. Thaw overnight in the fridge and bake as directed, adding 10–15 minutes to covered bake time if still cold. Baked leftovers can be frozen in portions for up to 2 months; thaw and reheat gently.
Food safety: Don’t leave baked casserole at room temperature more than 2 hours. Cool and refrigerate promptly.

Pro chef tips

Slice uniformly: Aim for 1/8–1/4-inch potato slices so they cook evenly. A mandoline speeds this up — use the guard to avoid injuries.
Caramelize properly: Low and steady heat with occasional stirring gives the sweetest onions. If they’re browning but not softening, add a tablespoon of water to deglaze and continue cooking.
Flavor depth: Stir a teaspoon of French onion soup mix or a splash of beef broth into the caramelized onions for a deeper savory note.
Cheese melt: Gruyère melts beautifully and adds nuttiness; if using cheddar, combine with a melting cheese like Monterey Jack to avoid oily separation.
Avoid watery bake: If your potatoes are very starchy, pat slices dry after rinsing to remove excess surface starch before layering.

For another French-onion-forward comfort dish in a different format, check out this crockpot French onion meatballs recipe for inspiration: Crockpot French Onion Meatballs.

Creative twists

Bacon & thyme: Scatter cooked crisp bacon and fresh thyme between layers for a smoky finish.
Mushroom and leek: Add sautéed mushrooms and leeks with the onions for earthiness.
Vegetarian boost: Stir some cooked white beans into a layer for extra protein.
Lighter version: Use half-and-half instead of heavy cream and a mix of Gruyère and lower-fat Swiss.
Herb crust: Top with panko mixed with melted butter and parsley for a crunchy finish.

Your questions answered

Q: Can I par-cook the potatoes first?
A: It’s not necessary if you slice thinly (1/8–1/4 inch). If you prefer, briefly parboil slices for 3–4 minutes to speed baking and ensure tenderness.

Q: Which potato is best—Russet or Yukon Gold?
A: Yukon Gold gives a creamier, waxy texture and holds shape well. Russets produce a softer, more mashed-like interior. Both work; choose based on texture you prefer.

Q: Can I make this dairy-free?
A: Yes—use full-fat coconut milk or a cashew cream substitute, and swap dairy cheese for a high-quality vegan melting cheese. Flavor will shift slightly but remain comforting.

Q: Is this safe to reheat more than once?
A: For food safety, only reheat the portion you plan to eat. Repeated cooling and reheating increases bacterial risk.

Q: How can I make this ahead?
A: Assemble the casserole, cover, and refrigerate up to 24 hours before baking. Add 10–15 minutes to the covered baking time if chilling makes it colder.

Conclusion

This French Onion Potato Bake is a forgiving, make-ahead-friendly dish that balances sweet caramelized onions with creamy potatoes and melty cheese—perfect for weeknights or special dinners. For more recipes in the same vein, see this detailed take on a Creamy Potato Bake with French Onion Soup – Peter’s Food and a tested version at French Onion Scalloped Potatoes Recipe | The Kitchn.