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5 from 6 votes

Easy Au Gratin Potatoes Recipe

Layers of thinly-sliced potatoes, a creamy sauce and two different types of cheese make this the best au gratin potatoes recipe you'll ever taste!
Course Side Dish
Cuisine French
Keyword au gratin potatoes, au gratin potatoes recipe easy, creamy au gratin potatoes, easy au gratin potatoes, easy au gratin potatoes recipe, potato au gratin recipe, potatoes au gratin
Prep Time 20 minutes
Cook Time 1 hour 10 minutes
Cooling Time 5 minutes
Total Time 1 hour 35 minutes
Servings 8 people
Calories 344kcal
Author Blair Lonergan

Equipment

Ingredients

  • 3 tablespoons salted butter
  • 3 tablespoons all-purpose flour
  • 2 cloves garlic, minced
  • 1 cup whole milk
  • 1 cup heavy cream
  • 1 ½ teaspoons minced fresh thyme leaves (or ½ teaspoon dried thyme)
  • Kosher salt and ground black pepper, to taste
  • ⅛ teaspoon freshly-grated nutmeg
  • ½ cup grated cheddar cheese
  • ½ cup grated Gruyere cheese
  • 2 ½ lbs. russet potatoes (about 5 medium), peeled and sliced ⅛-inch thick (or sub Yukon Gold potatoes)

Instructions

  • Preheat oven to 400°F. Grease a 2-quart baking dish and set aside.
  • Melt the butter in a large skillet over medium heat. Whisk in the flour and garlic; cook for 1 minute. Gradually whisk in the milk and cream. Cook, whisking, until the sauce thickens, about 2 minutes.
    Making the roux for au gratin potatoes in a skillet.
  • Add the thyme, salt, pepper, nutmeg, and half of each cheese. Whisk for about 1 minute until the cheese is fully melted. Taste and adjust seasoning as needed.
  • Arrange half of the potatoes in the prepared baking dish. Season lightly with salt. Pour half the sauce over the top. Layer the remaining potatoes on top, season again, and pour the rest of the sauce over everything. Sprinkle with the remaining cheese.
    Layering ingredients for au gratin potatoes in a baking dish.
  • Cover and bake for 50 to 60 minutes, until the potatoes are just about tender. Remove the cover and bake for another 15 to 20 minutes until the top is golden and bubbling.
    Horizontal overhead shot of a white baking dish full of au gratin potatoes.
  • Let the dish rest for 10 to 15 minutes before serving.
    Square overhead shot of au gratin potatoes in a serving bowl.

Notes

  • Potato choice: Russet potatoes give the creamiest sauce due to their higher starch content. Yukon Golds work well too and hold their shape a bit more.
  • Slice evenly: A mandoline makes ⅛-inch slices fast and consistent. Uneven slices cook unevenly.
  • Grate your own cheese: Pre-shredded cheese contains anti-caking agents that can make the sauce grainy. Fresh-grated melts much more smoothly.
  • Thicken the sauce first: Make sure the sauce is bubbling and thickened before layering. This prevents a watery finished dish.
  • Cover during baking: Keeping the dish covered for the first part of baking traps steam and helps the potatoes cook through evenly.
  • Rest before serving: The 10 to 15 minute rest lets the sauce firm up for cleaner, creamier scoops.
  • Add-ins: A handful of finely diced onion or bits of diced ham between the layers makes a heartier version.
  • Make-ahead: Assemble up to 24 hours ahead. Refrigerate covered. Let sit at room temperature for 30 minutes before baking.
  • Storage: Leftovers keep for 3 to 4 days in the refrigerator, covered.
  • Reheating: Warm at 350°F covered with foil for 20 to 30 minutes. Stir in a splash of milk or cream first if the sauce has thickened up.

Nutrition

Serving: 1/8 of the recipe | Calories: 344kcal | Carbohydrates: 30g | Protein: 9g | Fat: 21g | Saturated Fat: 13g | Trans Fat: 1g | Cholesterol: 72mg | Sodium: 141mg | Potassium: 672mg | Fiber: 2g | Sugar: 3g | Vitamin A: 768IU | Vitamin C: 8mg | Calcium: 208mg | Iron: 1mg