Potatoes Au Gratin

Potatoes Au Gratin

Course Side Dish
Prep Time 30 minutes
Cook Time 1 hour 30 minutes
Servings 8
Calories 292kcal


  • 2.5 pounds potatoes preferably red
  • 1 onion
  • 3 tbsp butter
  • 3 tbsp flour
  • 1 tsp mustard powder
  • 2 cup milk
  • 1 cup cheddar cheese shredded
  • ½ cup gruyere cheese shredded
  • salt & pepper to taste


  • Preheat oven to 400°F.
  • Wash potatoes and slice into ⅛” thin slices. Slice onion as thin as possible.
  • Layer potatoes and onions in little stacks. Place stacks upright in a greased casserole 2.5qt to 3qt dish.
  • Melt butter & flour in a saucepan and cook 2-3 minutes. Add seasonings and milk. Whisk over medium heat until thick and bubbly. Remove from heat and stir in cheeses until melted.
  • Spoon cheese sauce over potatoes. Cover with foil (sprayed with cooking spray) and bake 60 minutes.
  • Remove foil and bake an additional 20-30 minutes or until lightly browned and potatoes are cooked. Cool 15 minutes before serving.


Slice potatoes as thinly as possible.
Shred your own cheese from a block for the best results. Fresh herbs (such as thyme or rosemary) and garlic can be added to the sauce if desired.
To reduce baking time, wrap casserole dish in plastic wrap before adding the cheese sauce and microwave on full power for about 10 minutes (be careful, it will be hot when removing the plastic wrap). Add the cheese sauce and bake as directed for about 45-55 minutes.
Additional cheese (cheddar or parmesan) can be sprinkled on top once the foil is removed if desired.


Calories: 292kcal | Carbohydrates: 31g | Protein: 11g | Fat: 14g | Saturated Fat: 8g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 3g | Trans Fat: 0.2g | Cholesterol: 42mg | Sodium: 217mg | Potassium: 732mg | Fiber: 3g | Sugar: 5g | Vitamin A: 453IU | Vitamin C: 29mg | Calcium: 281mg | Iron: 1mg