Potatoes Au Gratin

5 stars from 1 review

Our favorite Potatoes Au Gratin recipe, featuring thinly sliced potatoes baked in a decadent cheese sauce. Golden, bubbly nostalgia in a pan!

Author: Donna Elick

Servings:

Prep Time15

Cook Time1 25

Total Time1 40

Ingredients

4 tablespoons unsalted butter
1/4 cup all-purpose flour
2 cups whole milk
1 cup heavy cream
1 ½ teaspoons kosher salt
1/2 teaspoon fresh ground black pepper
1/2 teaspoon garlic powder
1/2 teaspoon onion powder
8 ounces sharp cheddar cheese freshly shredded
3 pounds Yukon Gold potatoes thinly sliced into 1/8-inch rounds (skins optional)
fresh herbs garnish (optional)
4 ounces sharp cheddar cheese

Instructions

Preheat the Oven: Preheat oven to 375°F. Grease or butter a 9 x 13-inch baking dish and set aside.
Prepare the Cheese Sauce: In a large pot, melt 4 tablespoons unsalted butter over medium heat. Whisk in 1/4 cup all-purpose flour and cook for 1–2 minutes, stirring constantly, to eliminate the raw flour taste. Slowly pour in 2 cups whole milk and 1 cup heavy cream while whisking to prevent lumps. Add 1 ½ teaspoons kosher salt, 1/2 teaspoon fresh ground black pepper, 1/2 teaspoon garlic powder, and 1/2 teaspoon onion powder. Bring to a gentle simmer and whisk until smooth and thickened, about 3–5 minutes.
Add Cheese to the Sauce: Remove from heat and stir in 8 ounces sharp cheddar cheese until melted and smooth. Taste and adjust seasoning if needed.
Combine Potatoes and Sauce: Add 3 pounds Yukon Gold potatoes directly into the cheese sauce. Stir until all slices are well coated.
Assemble the Dish: Pour the potato mixture into the prepared baking dish, spreading evenly. Sprinkle 4 ounces sharp cheddar cheese over the top. Cover tightly with foil.
Bake Covered: Bake for 60 minutes, until the potatoes begin to soften.
Finish Baking: Remove foil and continue baking for 15–20 minutes, until the potatoes are fork-tender and the top is golden and bubbling.
Optional Broil: For a crispier top, broil for 2–3 minutes, watching closely to prevent burning.
Rest and Serve: Let the dish rest for 5 minutes before serving. This allows the sauce to set slightly for perfect slices.

Notes

Make-Ahead Tips: Assemble the dish up to 1 day ahead without baking. Cover tightly with foil and refrigerate. When ready to bake, add 15–20 minutes to the covered bake time.

Storage: Store leftovers in an airtight container in the refrigerator for up to 3 days.

Reheating Tips: Reheat individual servings in the microwave at 50% power for 1–2 minutes, stirring halfway. Add a splash of milk or cream if the sauce thickens too much.

Freezing Tips: Cool completely, then cover tightly with plastic wrap and foil. Freeze for up to 3 months. Thaw overnight in the refrigerator, then reheat in a 350°F oven for 35–40 minutes until warmed through. Texture will soften slightly due to the dairy, but flavor will remain rich and delicious.

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