Easy Au Gratin Potatoes Recipe

5 from 6 votes

Layers of thinly-sliced potatoes, a creamy sauce and two different types of cheese make this the best au gratin potatoes recipe you'll ever taste!

Course Side Dish

Cuisine French

Keyword au gratin potatoes, easy au gratin potatoes recipe, potatoes au gratin

Prep Time 20

Cook Time 1 10

Cooling Time 5

Total Time 1 35

Servings people

Calories 344kcal

3 tablespoons salted butter
3 tablespoons all-purpose flour
2 cloves garlic, minced
1 cup whole milk
1 cup heavy cream
1 ½ teaspoons minced fresh thyme leaves (or ½ teaspoon dried thyme)
Kosher salt and ground black pepper, to taste
⅛ teaspoon freshly-grated nutmeg
½ cup grated cheddar cheese
½ cup grated Gruyere cheese
2 ½ lbs. russet potatoes (about 5 medium), peeled and sliced ⅛-inch thick (or sub with Yukon Gold potatoes)

Preheat oven to 400°F. Grease a 2-quart baking dish; set aside.
In a large skillet, melt the butter over medium heat. Whisk in the flour and garlic; cook for 1 minute. Gradually whisk in the milk and cream; cook, whisking, until thickened, another 2 minutes or so.
Add the thyme, salt, pepper, nutmeg, half of the cheddar and half of the Gruyere. Whisk for about 1 more minute, making sure that all of the cheese is melted. Taste and season with additional salt and pepper, if necessary.
Arrange half of the potatoes in the prepared baking dish. Season with a little bit of salt. Pour half of the sauce over top. Arrange the remaining potatoes on top, season with another pinch of salt, and pour the remaining sauce over all. Sprinkle with remaining cheese.
Cover and bake for 50-60 minutes (or until the potatoes are just about tender), then uncover and bake until browned on top, an additional 15-20 minutes. Let rest for 10-15 minutes, then serve.