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Creamy, Cheesy Potatoes au Gratin Recipe
4.6 from 78 votes

Creamy, Cheesy Potatoes au Gratin Recipe

Creamy, Cheesy Potatoes au Gratin features thinly sliced russet potatoes layered with a rich cheese sauce made from melted butter, garlic, thyme, flour, cream, and a blend of Gruyere and white cheddar cheeses. The sauce thickens into a velvety coating that bakes alongside the potatoes to form a golden, bubbly crust. This dish provides tender potato slices infused with savory cheese and herb flavors, ideal as a comforting side dish.

Prep Time
10 mins
Cook Time
1 hr 5 mins
Total Time
1 hr 15 mins
Servings: 10 servings
Calories: 421 kcal
Course: Side Dish
Cuisine: French

Ingredients

  • 3 pounds russet potato scrubbed well and sliced into ⅛-th inch thick coins
Cheese Sauce
  • 4 tbsp butter
  • 3 prigs thyme or ½ tsp dried thyme, fresh leaves
  • 3 cloves garlic pressed or minced
  • 1/2 cup all-purpose flour
  • 1½ cups cream or half and half or milk
  • 1 tsp kosher salt
  • ½ tsp black pepper freshly ground
  • 2 cups gruyere cheese ½ cup divided for the topping, shredded
  • 2 cups White Cheddar Cheese ½ cup divided for the topping, shredded

Instructions

Make Cheese Sauce:
    Cup of Yum
  1. 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.
  2. Sprinkle in 4 tbsp of 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.
  3. 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.
  4. 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.
Layer and Bake
  1. 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.
  2. 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.
  3. 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.
  4. Let cool for 5-10 minutes before serving.

Notes

  • The dish can be baked in an oval or cast iron skillet as preferred.
  • Allow the casserole to cool before covering and refrigerating; it keeps well for 3-4 days.
  • Reheat leftovers covered in a 350°F oven for 20-30 minutes until warmed through.
  • Individual portions may be reheated in the microwave covered with a damp paper towel for 1-2 minutes.

Nutrition Information

Serving 1 serving Calories 421kcal (21%) Carbohydrates 32g (11%) Protein 18g (36%) Fat 25g (38%) Saturated Fat 15g (75%) Polyunsaturated Fat 1g (6%) Monounsaturated Fat 7g (35%) Trans Fat 0.2g (10%) Cholesterol 76mg (25%) Sodium 634mg (26%) Potassium 669mg (14%) Fiber 2g (8%) Sugar 3g (6%) Vitamin A 761IU (15%) Vitamin C 9mg (10%) Calcium 489mg (49%) Iron 2mg (11%)

Nutrition Facts

Serving: 10 servings

Amount Per Serving

Calories 421

% Daily Value*

Serving 1 serving
Calories 421kcal 21%
Carbohydrates 32g 11%
Protein 18g 36%
Fat 25g 38%
Saturated Fat 15g 75%
Polyunsaturated Fat 1g 6%
Monounsaturated Fat 7g 35%
Trans Fat 0.2g 10%
Cholesterol 76mg 25%
Sodium 634mg 26%
Potassium 669mg 14%
Fiber 2g 8%
Sugar 3g 6%
Vitamin A 761IU 15%
Vitamin C 9mg 10%
Calcium 489mg 49%
Iron 2mg 11%

* Percent Daily Values are based on a 2,000 calorie diet.