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–+ servings
A generous slice of creamy Au Gratin Potatoes with a golden, cheesy, baked top on a white plate.

Au Gratin Potatoes (Classic)

This classic Au Gratin Potatoes recipe features thinly sliced potatoes and onions baked in a rich, creamy Cheddar cheese sauce. This side dish is perfect for family gatherings and holiday meals.
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Prep Time 20 minutes
Cook Time 1 hour 30 minutes
Total Time 1 hour 50 minutes
Servings: 4 people
Course: Side Dish
Cuisine: American
Calories: 499
Ingredients Equipment Method Nutrition Notes

Ingredients
  

For the Potatoes
  • 4 medium russet potatoes thinly sliced
  • 1 medium onion sliced into rings
  • salt and ground black pepper to taste
For the Sauce
  • 3 tablespoons butter
  • 3 tablespoons all-purpose flour
  • 1/2 teaspoon salt
  • 2 cups milk
  • 1 1/2 cups shredded Cheddar cheese

Equipment

  • 2-quart casserole dish
  • Medium saucepan

Method
 

  1. Preheat your oven to 400 degrees F (200 degrees C). Grease a 2-quart casserole dish with butter.
  2. Layer half of the sliced potatoes in the bottom of the prepared casserole dish. Season this layer with salt and pepper.
  3. Layer the onion slices over the potatoes, then top with the remaining potatoes. Season this top layer again with salt and pepper.
  4. Melt the butter in a medium saucepan over medium heat. Whisk in the flour and 1/2 teaspoon of salt. Cook, whisking constantly, until the raw flour flavor has cooked off, about 1 minute.
  5. Gradually whisk in the milk. Cook, whisking constantly, until the mixture has thickened, which should take 3 to 5 minutes.
  6. Remove the saucepan from the heat. Stir in the shredded Cheddar cheese all at once. Cook, stirring constantly, until the cheese is completely melted, about 30 to 60 seconds.
  7. Pour the cheese sauce evenly over the potatoes in the casserole dish. Cover the dish tightly with aluminum foil.
  8. Bake in the preheated oven until the potatoes are tender and the sauce is bubbly, about 1 1/2 hours.

Nutrition

Calories: 499kcalCarbohydrates: 49gProtein: 20gFat: 25g

Notes

For an extra golden-brown top, remove the aluminum foil during the last 15 minutes of baking.

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