Creamy, Cheesy Potatoes au Gratin Recipe

a spoon scooping up potatoes au gratin from a dish

4.62 from 26 votes

Creamy, Cheesy Potatoes au Gratin Recipe

Your holiday table needs this creamy, cheesy potatoes au gratin recipe featuring thinly sliced potatoes baked in a rich gruyere and cheddar sauce with crispy cheese topping. A perfectly decadent side dish!

Prep Time10

Cook Time1 5

Total Time1 15

Course: Side Dishes

Cuisine: French

Servings: servings

Calories: 484kcal

Author: Eden Westbrook

Equipment

Mandoline this is the one I use

Ingredients

3 pounds russet potatoes scrubbed well and sliced into ⅛-th inch thick coins

Cheese Sauce

4 tablespoon butter
3 sprigs fresh thyme leaves or ½ teaspoon dried thyme
3 cloves garlic pressed or minced
¼ cup all purpose flour
1½ cups cream or half and half or milk
1 teaspoon kosher salt
½ teaspoon black pepper freshly ground
2 cups shredded gruyere cheese ½ cup divided for the topping
2 cups shredded white cheddar cheese ½ cup divided for the topping

Instructions

Make Cheese Sauce

In a medium saucepan, melt the butter over medium low heat. As it's melting, add in the thyme leaves and garlic and let cook until the garlic is fragrant, about 2 minutes.
4 tablespoon butter, 3 sprigs fresh thyme leaves, 3 cloves garlic
Sprinkle in the flour, a little at a time, while continuously whisking. Don’t dump it all at once, this helps prevent clumps. Cook for about 1 minute to cook out the raw flour.
¼ cup all purpose flour
Gradually pour in the cream, whisking constantly. The mixture will seize up at first and turn into a paste, but keep whisking and adding cream until it forms a smooth, liquidy sauce. Allow it to simmer gently over medium heat and reduce until it’s thick enough to coat the back of a spoon (nappé). Because we're not using a lot of liquid compared to the roux, it won't take very long, around 3 minutes.
1½ cups cream
Turn off the heat and stir in ½ cup of shredded gruyere and ½ cup of shredded white cheddar, a handful at a time. Stir until melted before adding another handful. Be careful not to add the cheese while the heat is on to avoid a broken, gritty, greasy cheese sauce. Taste and season with salt and pepper.
1 teaspoon kosher salt, ½ teaspoon black pepper, 2 cups shredded gruyere cheese, 2 cups shredded white cheddar cheese

Layer and Bake

Preheat oven to 350 degrees F. Layer the sliced potatoes in a baking dish, covering the entire bottom of the dish with one single layer.
3 pounds russet potatoes
Pour a layer ⅓ cup of the cream sauce over the first layer of potatoes, then cover evenly with a mixture of the cheddar and gruyere. Repeat until you've reached almost the top of your baking dish, about 3-4 layers ending with the last bit of cheese sauce. Cover the top with the last 1 cup of your cheese.
2 cups shredded gruyere cheese, 1½ cups cream
Cover with aluminum foil and Bake in the oven for 30 minutes. Remove the foil and continue baking for an additional 30 minutes, or until the top is golden brown and bubbly.
Let cool for 5-10 minutes before serving.

Notes

Baking Dish Notes: My oval dish measures 2.72'' H X 13.9'' L X 8.43'' W, but a 9x13 rectangular baking dish is a great swap. I have also made this in a 10 inch cast iron skillet without a problem!

Storage and Reheating

To store potatoes au gratin, let the casserole dish cool to room temperature before covering it tightly with foil or plastic or transferring it to an airtight container. It will keep in the refrigerator for up to 3-4 days.

When it’s time to reheat, the oven is your best option. Preheat the oven to 350°F (180°C/Gas Mark 4/160ºC fan). If the dish has been stored in the fridge, cover it with foil and bake for 20-30 minutes, or until warmed through.

If you’re short on time, you can reheat individual portions in the microwave. Place a portion in a microwave-safe dish, cover with a damp paper towel, and heat for 1-2 minutes, stirring halfway through for even warming.

Nutrition