Potatoes Au Gratin Recipe

Looking for a family favorite dish? Look no further! Sharp Chef Michelle, the blogger for Sunkissed Kitchen, has provided us with the perfect dish to please even the pickiest eaters. This Potatoes Au Gratin recipe is made to perfection in the Sharp Smart Combi Built-In Steam Oven.


6 potatoes 5 cups sliced potatoes
1 onion
3 tablespoons butter
3 tablespoons all-purpose flour
1 1/2 teaspoons sea salt
1/4 teaspoon black pepper
2 cups whole milk
1 cup sharp white cheddar cheese shredded
1 tablespoon fresh thyme


  1. Using a mandolin slicer, very thinly slice the potatoes and onion. Set aside.
  2. Preheat the Superheated Steam Oven to Convection/Bake at 350º F for 1 hour.
  3. Make the cheese sauce by first adding the butter to a large skillet over medium heat on your Sharp Cooktop. As the butter melts, add in the flour, stirring to create a roux.
  4. Add salt and pepper to the roux, and continue to stir for about a minute until the mixture is bubbling.
  5. Slowly add the milk about 1/2 cup at a time, stirring as the milk warms and begins to bubble. Stir to remove any lumps in the mixture. Continue adding the milk and stirring until all the milk has been added.
  6. Once the milk is smooth, add the cheese, and stir to melt it into the sauce. Add the thyme, and then remove the mixture from heat.
  7. Into a 10-inch round baking dish (a tart pan or pie plate works perfectly for this), add potatoes and onions. Mix the thinly sliced onions into the rounds of potatoes so there is an onion for every few slices of potato. Add them in a round pattern around the outside of the dish. Then, continue to add the rest in an inner circular pattern.
  8. Pour the cheese sauce over the potatoes, and use a fork to work it in between some of the layers of potato and onion, until it’s settled into the dish.
  9. Cover the baking dish with foil, and bake for 1 hour. Remove the foil, reset the oven to Bake/Convection at 350º for 30 minutes, and continue to bake to brown the top.


*If you don’t have a mandolin, very thinly slice the potatoes and onions using a sharp chef’s knife.

**Save time making this dish by adding the potatoes and onions to a 9×13 inch baking dish, pouring the cheese sauce over the top, and using a fork to coat the vegetables. This dish is delicious, even if you don’t have time for a perfect presentation.

***Gruyere cheese makes a great sub for the cheddar if you’d like a stronger flavored cheese sauce.

*** First appeared on July 11, 2022 on Simply Better Living ***