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Cheesy Au Gratin Potatoes

Layers of thinly sliced potatoes baked in a creamy cheddar and Gruyere sauce with a bubbly golden cheese top. The ultimate cheesy holiday side dish.
Print Recipe
Prep Time 25 minutes
Cook Time 1 hour 15 minutes
Resting 15 minutes
Total Time 1 hour 55 minutes
Course Side Dish
Cuisine American
Servings 10 servings
Calories 360 kcal

Ingredients
  

Potatoes:

  • 3 lb Yukon Gold or russet potatoes peeled and sliced 1/8 inch thick

Cheese sauce:

  • 4 tbsp butter
  • 2 cloves garlic minced
  • 1/4 cup all-purpose flour
  • 2 1/2 cups whole milk warmed
  • 1/2 cup heavy cream
  • 1 1/2 tsp kosher salt
  • 1/2 tsp black pepper
  • 1/4 tsp smoked paprika

Cheese:

  • 2 cups sharp cheddar freshly shredded, divided
  • 1 cup Gruyere freshly shredded, divided
  • 1/2 cup grated Parmesan

Instructions
 

  • Heat the oven to 400°F (200°C). Butter a 9x13-inch baking dish.
  • Melt the butter in a saucepan over medium heat. Add the garlic and cook 30 seconds. Whisk in the flour and cook 1 minute.
  • Slowly whisk in the warm milk and cream. Simmer, whisking, until thick enough to coat a spoon, 3 to 5 minutes. Remove from the heat and stir in the salt, pepper, paprika, 1 cup cheddar and 1/2 cup Gruyere until smooth.
  • Layer half the potatoes in the dish. Pour half the sauce over them. Add the rest of the potatoes and the rest of the sauce, pressing the potatoes down into the sauce.
  • Cover with foil and bake for 45 minutes. Uncover, top with the remaining cheddar, Gruyere and the Parmesan, and bake 25 to 30 minutes more, until the potatoes are tender and the top is golden and bubbly.
  • Rest 15 minutes before serving so the sauce sets.

Notes

Make ahead: Assemble without the top layer of cheese up to 1 day ahead. Refrigerate, then add 15 minutes to the covered baking time.
Storage: Refrigerate leftovers within 2 hours for up to 4 days.
Reheat: Cover and warm at 350°F (175°C) for 20 to 25 minutes.
Variations: Use all cheddar, add crumbled bacon between the layers, or add sliced green onions on top.
Keyword au gratin potatoes, cheesy au gratin potatoes, christmas side dish, potatoes au gratin