Creamy au Gratin Potatoes

Creamy au Gratin Potatoes

from allrecipes.com
Dinner
120 min
499 kcal / serving

Au gratin potatoes made with thinly sliced potatoes and onions baked in a decadently rich and creamy cheese sauce until tender and bubbling.

Ingredients

  • 4 mediumrusset potatoes, thinly sliced
  • 1 mediumonion, sliced into rings
  • salt and ground black pepper to taste
  • 3 tablespoonsbutter
  • 3 tablespoonsall-purpose flour
  • ½ teaspoonsalt
  • 2 cupsmilk
  • 1 ½ cupsshredded cheddar cheese

Directions

  1. 1

    Gather all ingredients. Preheat the oven to 400 degrees F (200 degrees C). Grease a 2-quart casserole dish with butter.

  2. 2

    Layer 1/2 of the potatoes in the bottom of the prepared casserole dish; season with salt and pepper.

  3. 3

    Layer onion slices over top, then top with with remaining potatoes. Season again with salt and pepper.

  4. 4

    Melt butter in a medium saucepan over medium heat. Whisk in flour and salt; cook, whisking constantly, until raw flour flavor has cooked off, about 1 minute.

  5. 5

    Gradually add milk, about 1/4 cup at a time, whisking well after each addition to incorporate; the gradual addition and whisking of milk will help avoid lumps in your sauce.

  6. 6

    Cook, whisking constantly, until the mixture has thickened, 3 to 5 minutes.

  7. 7

    Stir in cheese all at once; cook, stirring constantly, until melted, 30 to 60 seconds.

  8. 8

    Pour cheese sauce over the potatoes, and cover the dish with aluminum foil.

  9. 9

    Bake in the preheated oven until potatoes are tender and sauce is bubbly, about 1 ½ hours.