If there’s one food I can never resist, it’s potatoes. Whether crispy French fries or creamy mashed potatoes, they’re the ultimate comfort food! But when you want something extra indulgent, there’s nothing quite like a bubbling, golden-brown potato gratin. It’s rich, cheesy, and perfectly satisfying—ideal for holidays, dinner parties, or cozy nights in.
Potato gratin, also known as potatoes au gratin, features thinly sliced potatoes baked in a luxurious cream sauce and topped with melted cheese. There are two common ways to make the sauce: with heavy cream for an ultra-decadent version, or with a lighter béchamel sauce (a buttery, milk-based sauce thickened with flour). Either way, it’s hard to go wrong!
I like to season the sauce with sautéed onions, garlic, thyme, and a pinch of nutmeg for extra flavor. Then comes the cheese! Gruyère is a classic choice, but feel free to mix and match with your favorites—cheddar, mozzarella, havarti, Swiss, or a blend all work beautifully.
Yes, slicing the potatoes and arranging them takes a little effort (a mandoline makes it easier!), but once it’s assembled, you can just pop it in the oven and let that creamy, cheesy magic happen.
Ingredients
Serves: 8 | Prep Time: 20 min | Cook Time: 1 hr 10 min | Total: 1 hr 30 min
- 3 tablespoons butter
- 1 small onion, finely diced
- 1 clove garlic, minced or grated
- 1 teaspoon fresh thyme (or ½ tsp dried thyme)
- 3 tablespoons flour (use gluten-free if needed)
- 1½ cups milk (or use heavy cream for a richer version)
- 1½ cups Gruyère cheese, shredded
- Pinch of nutmeg (optional)
- Salt and pepper, to taste
- 4 pounds potatoes (Yukon gold or russet), thinly sliced
Instructions
- Make the sauce:
In a medium saucepan, melt butter over medium heat. Add onions and cook until soft, 3–5 minutes. Stir in garlic and thyme and cook for another 30 seconds until fragrant. - Thicken:
Sprinkle in the flour and cook for about a minute, stirring constantly, until it starts to turn lightly golden. Slowly whisk in the milk and cook until thickened, 1–2 minutes. - Add cheese:
Lower the heat and stir in ½ cup of the shredded cheese until melted. Season with nutmeg (if using), salt, and pepper to taste. - Layer the potatoes:
Lightly grease a large baking dish or cast iron skillet. Spread a thin layer of sauce on the bottom. Then layer the potatoes, dipping each slice into the sauce (if desired) as you arrange them in the dish. Pour any remaining sauce over the top. - Top and bake:
Sprinkle the remaining cheese over the potatoes. Cover with foil and bake in a preheated 350°F (180°C) oven for 45–60 minutes, or until the potatoes are fork-tender. Remove foil and bake another 10–15 minutes until golden and bubbly.
Tips & Variations
- Cheese: Swap Gruyère for cheddar, mozzarella, Swiss, havarti, or even a combo!
- Creamy option: Replace milk and flour with 1½ cups heavy cream for a richer texture.
- Extra flavor: Stir in cooked crumbled bacon, or top with grated Parmesan or Pecorino Romano.
- Potatoes: Yukon golds are buttery and hold their shape, while russets give a fluffier texture.
Nutrition (per serving):
Calories: 341 | Fat: 13g | Carbs: 45g | Fiber: 5g | Protein: 11g