Au Gratin Potatoes
- Preparation time: 10 minutes
- Baking time: 1½ hours
- 2 pounds red or gold potatoes, sliced into very thin rounds (about 6 medium potatoes)
- Salt for seasoning the potatoes
- 1 medium onion, chopped
- ¼ butter (½ stick)
Dry Ingredients For Sauce:
- 2 tablespoons flour
- ¼ teaspoon ground rosemary
- ¼ teaspoon ground thyme
- ¼ teaspoon paprika
- 1 teaspoon salt
- ¼ teaspoon ground black pepper
- Dash of cayenne pepper
Milk for Sauce:
- 1 cup milk
- 1 cup buttermilk
Cheese For Sauce:
- 1½ cups grated medium or sharp cheddar cheese
- ½ cup grated medium or sharp cheddar cheese
- ¼ cup fine dry bread crumbs
If baking the potatoes for 1½ hours, preheat oven to 325°.
- If baking the potatoes for 1 hour, preheat oven to 375°.
- Scrub potatoes and remove any blemishes.
- I leave the peels on, but you can peel if you prefer.
- Slice the potatoes into very thin rounds (⅛-inch or less).
- Place potatoes in layers in an ungreased 9x12 rectangular pan, or 3-quart casserole dish; sprinkling each layer with a dash of salt as you go.
- In a small bowl, whisk together flour and seasonings; set aside.
- Grate cheese and set aside. 1½ cups will be used for the sauce, the other ½ cup will be used for the topping.
- Melt butter on medium-low heat in a shallow skillet.
- Add chopped onion to butter and cook until tender; about 5 minutes.
- Stir the seasoning mixture into the onion and butter mixture.
- Cook over low heat, stirring constantly, until mixture is bubbly.
- Stir in milk and buttermilk, heat to a simmer and cook for 1 minute, stirring constantly.
- Remove from heat.
- Add 1½ cups of cheese to the skillet.
- Whisk the 1½ cups of cheese into the milk mixture until incorporated.
- Pour the cheese sauce over the potatoes.
- If your oven is set at 325°, bake uncovered for 1½ hours.
- If your oven is set at 375°, bake uncovered for 1 hour.
- 15 minutes before the casserole is done baking, sprinkle the remaining ½ cup grated cheese and bread crumbs over the top.
- Bake for the remaining 15 to 20 minutes until the top is brown and bubbly.