PERFECT Au Gratin Potatoes

Kimberly Killebrew

Perfectly creamy, cheesy and flavorful, these are au gratin potatoes at their very best!

4.66 from 245 votes

Prep Time 10

Cook Time 1 30

Total Time 1 40

Course Side Dish

Cuisine French

Servings servings

Calories 397 kcal

2 pounds moderate starch potatoes like Yukon Gold , thinly sliced (Russets are high starch and get mushy/do not hold their shape)
3 tablespoons butter
3 tablespoons all-purpose flour
1/2 cup finely chopped yellow onion
2 cloves garlic minced
2 cups whole milk
1/2 cup heavy cream
1 1/2 teaspoons salt
1/4 teaspoon freshly ground black or white pepper (optional)
1 1/2 cups shredded Cheddar cheese (do not use pre-shredded, it's dusted with cellulose and doesn't melt as well; another fabulous option is half Gruyere/half Emmentaler)
1/3 cup grated Parmesan cheese divided in half
chopped parsley for garnish

Preheat the oven to 350 degrees F.
Heat the butter in a large saucepan over medium-high heat and add the onions and cook until soft and translucent, 5-6 minutes. Add the garlic and cook for another minute. Add the flour and stir to combine. Cook for a minute or two. Add the milk and cream, stirring continually to prevent clumping. Slowly bring to a boil, reduce the heat and simmer until slightly thickened.
Add the cheddar cheese, parmesan cheese and salt and stir until melted. Add the potatoes and stir until thoroughly combined.
Pour the mixture into a 2 quart casserole dish. Sprinkle with the remaining Parmesan cheese. Cover with foil. Bake for 1 hour or until the potatoes are tender (time can vary depending on how thickly the potatoes are sliced).
Uncover and bake for another 20 minutes or until the top is lightly browned.
Let sit for about 5 minutes before serving. Sprinkle with some chopped parsley for garnish if desired.

*Make Ahead: See section in blog post about making this dish ahead of time.

Keyword Au Gratin Potatoes

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