Mashed Potato au Gratin

4.9
(23)

This spectacular mashed potato au gratin is my favorite potato side dish, mashed potatoes, topped with my other favorite potato side dish, potatoes au gratin. Beautiful, buttery mashed potatoes, with crusty, cheesy potatoes on top—it's a whole new exciting way to eat potatoes.

6
golden-brown casserole of potatoes au gratin on grey placemat with spoon in background
6
6
6
Prep Time:
40 mins
Cook Time:
1 hr 15 mins
Total Time:
1 hr 55 mins
Servings:
12

​​Somewhere, sometime, someone preparing a special occasion meal was frozen with indecision regarding whether to serve mashed potatoes or potatoes au gratin. Both are classic sides that pair perfectly with any fancy holiday main courses, so how to choose? I mean, you can’t make both. Or can you? 

Okay, I’ll admit to being that certain someone struggling with the decision. So I stacked them up and was able to have my mashed potatoes and potatoes au gratin too.

Besides its spectacular appearance and being fairly simple to make, the texture of the final dish was quite impressive. The mashed potatoes felt and tasted like mashed potatoes and, while the sliced layer of potatoes on top wasn’t as creamy as the classic version, it was everything you want in a potatoes au gratin recipe and more. 

So, whether it’s for a holiday dinner, or just some random weeknight, I really do hope you give this a try soon. Enjoy! 

More recipes: Try the latest and greatest recipes from Chef John!

Cook Mode (Keep screen awake)

Ingredients

Original recipe (1X) yields 12 servings

Mashed Potato Base:

  • 6 large russet potatoes, peeled and quartered

  • 3 tablespoons kosher salt

  • 1/2 cup cold unsalted butter, cut in pieces

  • salt to taste

  • 1 pinch cayenne

  • 3/4 cup milk

  • 4 ounces Comte, Gruyere, or Cheddar cheese, shredded

Au Gratin Potato Topping:

  • 4 large russet potatoes, peeled and halved

  • 2 teaspoons kosher salt

  • freshly ground black pepper to taste

  • 2 tablespoons melted butter

  • 2 ounces Comte cheese, Gruyere cheese, or Cheddar cheese, shredded

  • 1/2 cup grated Parmigiano-Reggiano cheese

Directions

  1. Preheat the oven to 450 degrees F (230 degrees C). Butter a 13x9-inch baking dish.

  2. For the mashed potato, add quartered russet potatoes to a pot with 3 tablespoons salt and enough water to cover by 2 inches. Bring to a boil over high heat; reduce heat to medium and simmer until tender when pierced with a sharp knife, but not falling apart, 15 to 20 minutes. Drain very well.

  3. Return potatoes to the pot, and mash until almost smooth. Add butter, salt, and cayenne. Mash until smooth. 

  4. Add milk and the 4 ounces shredded cheese, and mash and mix until evenly combined. Spread evenly into the prepared baking dish, and smooth the top. Season the top with salt and freshly ground black pepper.

  5. For the au gratin potato layer, slice each half potato into 1/8-inch slices.

  6. Fan the potato out slightly at an angle, and place on top of mashed potatoes. Repeat with remaining potato halves to cover the surface, creating 4 rows across by 2 potato halves long, using 8 halves total. Depending on the size of potato and dish, you may have to adjust the layout to cover.

  7. Generously salt sliced potatoes, and brush generously with melted butter. Scatter the 2 ounces shredded cheese on top, and finish with grated Parmigiano-Reggiano.

  8. Bake in the preheated oven until sliced potatoes on top are tender when pierced with a knife, about 1 hour.

    golden-brown casserole of potatoes au gratin on grey placemat with spoon in background

    Chef John

Nutrition Facts (per serving)

411 Calories
16g Fat
55g Carbs
13g Protein
Nutrition Facts
Servings Per Recipe 12
Calories 411
% Daily Value *
Total Fat 16g 21%
Saturated Fat 10g 48%
Cholesterol 46mg 15%
Sodium 1437mg 62%
Total Carbohydrate 55g 20%
Dietary Fiber 6g 21%
Total Sugars 4g
Protein 13g 25%
Vitamin C 21mg 23%
Calcium 247mg 19%
Iron 3mg 15%
Potassium 1420mg 30%

* Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

** Nutrient information is not available for all ingredients. Amount is based on available nutrient data.

(-) Information is not currently available for this nutrient. If you are following a medically restrictive diet, please consult your doctor or registered dietitian before preparing this recipe for personal consumption.