Traditional Potatoes Au Gratin Casserole
You’ll never miss the boxed version after trying these easy potatoes!
Serves: 4Hands-on: 20 minutesTotal: 1 hour 20 minutesDifficulty: Medium
- 2 Tbsp. butter
- 1 onion, chopped
- 2 Tbsp. flour
- 2 cups 2% milk
- ½ tsp. salt
- ½ tsp. paprika
- ½ tsp. mustard powder
- ¼ tsp. pepper
- 1½ lbs. russet potatoes
- 3 oz. grated Monterey jack cheese
- Preheat the oven to 375°F and spray an 8" × 8" baking dish lightly with nonstick spray.
- Heat the butter over medium heat in a large saucepan. When hot, add the onion and cook, stirring occasionally, until the onion softens, 5 minutes.
- Whisk in the flour and slowly stream in the milk, whisking constantly to avoid lumps. Whisk in the salt, paprika, mustard powder, and pepper. Cook the sauce over medium heat until it thickens, about 5 minutes. Remove the sauce from the heat.
- Peel and slice the potatoes ⅛" thick, gently stirring the slices into the sauce mixture. Transfer the contents of the pot to the prepared casserole dish, spreading the potatoes so that they form an even layer and are submerged in the sauce. Sprinkle the casserole with the cheese.
- Bake the casserole, covered tightly with foil, until the potatoes are tender and cooked through, about 45 minutes. Remove the foil and cook for another 15–20 minutes until the top browns. Allow the casserole to cool for at least 10 minutes before serving, as sauce will thicken as it cools.