Name: French Onion Potato Gratin
Prep time: 1 h
Cook time: 1 h
Total time: 2 h
Ingredients: 2 tbsp butter; 2 tbsp olive oil; 3 large yellow onions, thinly sliced; 1 tsp sugar; 3 garlic cloves, minced; Salt and black pepper to taste; 2 lbs (900g) russet potatoes, thinly sliced; 1½ cups heavy cream; 1 cup grated Gruyère cheese; ½ cup grated Parmesan cheese; 1 tsp fresh thyme (optional)

This French Onion Potato Gratin is the perfect marriage of creamy, cheesy potato layers and the sweet richness of caramelized onions—think of it as comfort food with a gourmet twist. Great for holidays or a cozy family dinner.

Origin French Onion Potato Gratin

Gratin dishes originate from French cuisine, known for their rich, baked, creamy textures. The classic “gratin dauphinois” uses thinly sliced potatoes, cream, and cheese. This version combines the beloved flavors of French onion soup—caramelized onions and Gruyère cheese—with the traditional gratin method, creating a layered dish full of flavor, warmth, and French flair.

What I Love About This Recipe

I love how this recipe transforms simple pantry ingredients into something so rich and satisfying. The caramelized onions add a deep sweetness that pairs perfectly with the creamy potatoes and sharp Gruyère. Every bite is melty, savory, and layered with flavor. It’s a dish that feels luxurious but is surprisingly easy to make—and it always impresses.

French Onion Potato Gratin

Recipe by RecipeWikki

Servings

servings

Prep time

hour

Cooking time

hour

Calories

400

kcal

Ingredients

2 tbsp butter
2 tbsp olive oil
3 large yellow onions, thinly sliced
1 tsp sugar
3 garlic cloves, minced
Salt and black pepper to taste
2 lbs (900g) russet potatoes, thinly sliced
1½ cups heavy cream
1 cup grated Gruyère cheese
½ cup grated Parmesan cheese
1 tsp fresh thyme (optional)

Directions

Heat butter and olive oil in a large pan over medium heat. Add onions and sugar, and cook slowly, stirring frequently, until golden and caramelized (about 25–30 minutes). Stir in garlic near the end.
Preheat oven to 375°F (190°C). Grease a baking dish.
Layer half of the sliced potatoes in the dish. Season with salt, pepper, and thyme.
Add half of the caramelized onions, then pour over half of the cream and sprinkle with half of the cheeses.
Repeat with the remaining potatoes, onions, cream, and cheeses.
Cover with foil and bake for 40 minutes. Remove foil and bake for another 15–20 minutes until bubbly and golden.
Let rest for 10 minutes before serving.

Notes

Swap Gruyère with Swiss or mozzarella for a different flavor.
Prep the caramelized onions a day in advance to save time.

Perfect for Dinner Parties