Home » MASHED POTATO GRATIN {Cheesy!}

MASHED POTATO GRATIN {Cheesy!}

Move over plain potato side dish and serve this delicious Mashed Potato Gratin! Creamy potatoes, mixed with cheese, and topped with a crispy, buttery panko topping.

spoon of mashed potato gratin

If you’d rather skip my essential cooking tips and tricks and get straight to this delicious recipe – simply scroll to the bottom of the page where you can find the printable recipe card.

MASHED POTATO GRATIN

When I think of mashed potatoes, I think of the standard side dish that everyone loves. The family favorite that is easier to make than other potato gratins and can be whipped up in a jiffy.

Sometimes you need to elevate them without getting too fancy or blowing out the budget.

This Mashed Potato Gratin is just what you are looking for!

WHY THIS RECIPE IS AMAZING!

  • You can make it ahead of time
  • The buttery crispy topping is delicious!
  • A great way to use up leftover mashed potatoes
  • Freezes beautifully!
This post may contain affiliate links. As an Amazon Associate, I earn from qualifying purchases. Read my disclosure policy here.
labeled picture of mashed potato gratin ingredients

MASHED POTATO GRATIN INGREDIENTS

  • potatoes
  • sour cream
  • milk
  • cheese
  • egg

Potatoes – Russets are the best potato for this. I use 5 large one or roughly 3 pounds.

Sour Cream – Feel free to use full fat, reduced fat, or low fat works. You can also use plain Greek yogurt.

Milk – I use 1% but you can also use fat free. Substitute half and half if you would like even creamier potatoes.

Cheese – I use Emmentaler (Swiss cheese) but you can use Gruyere, cheddar, or mozzarella

Egg – 1 large is best here. Bring it to room temperature before beating.

Looking for more comfort food? Follow LTB on Pinterest!

HOW TO MAKE MASHED POTATO GRATIN

ONE: Heat oven to 375F. Peel and dice the potatoes. Place in a large pot and cover with cold water. Add 2 teaspoons salt. Bring to boil over high heat and cook until the potatoes are fork tender. Drain and return potatoes to the pot.

TWO: Gently mash the potatoes. Add the milk, sour cream, cheese, and butter. Mix to combine. Season with salt and pepper as desired.

THREE: Spray the baking dish with cooking spray to prevent sticking. Spread the potato mixture in the prepared baking dish. Top with panko bread crumbs.

FOUR: Bake at 375F for 20 minutes or until the top is golden brown. Remove from the oven and enjoy!

For the full recipe and detailed baking instructions, please see the recipe card at the end of this post.

casserole in a dish with a scoop missing

HOW TO STORE IT:

LEFTOVERS: Store any leftover mashed potato gratin in the refrigerator, in an air tight container, for up to 4 days.

REHEAT: To reheat, place in a 350F oven for 15 to 20 minutes until heated through. If the potatoes start to get a little dry, add 1/2 cup of broth, water, or milk and stir. Then bake.

FREEZE: Prep and wrap tightly in plastic wrap. Freeze for up to 2 months. Thaw overnight in the refrigerator, top with panko, cover with foil and bake as directed.

CAN I MAKE THIS AHEAD OF TIME?

Sure you can! Just prep and keep it covered and refrigerated until ready to bake. I think leaving off the panko crumbs until just ready to bake. This way they don’t get soggy.

spoon of mashed potatoes

WHY ARE MY MASHED POTATOES GLUEY OR GUMMY?

The main reason that mashed potatoes get gluey or gummy is over processing. Be sure to cook the potatoes until they are fork tender.

When you mash them, I like to use a potato masher or a wide fork. Just mash until most of the large chunks are gone.

Adding in the rest of the ingredients, be sure to gently fold them in and do not over mix!

TIPS FOR NO LEFTOVERS

  • Be sure to salt the water when cooking the potatoes so they get some extra seasoning!
  • Boil the potatoes in chicken broth for a richer flavor instead of plain water.
  • Choose your favorite cheese when mixing in.
  • Substitute 1 large egg for 2 egg yolks.
  • Use 1/2 cup of the potato water or warm milk when mashing the potatoes.
  • Mix the panko with 1 tablespoon of melted butter before sprinkling on top of the potato gratin. It will help them brown faster.
  • Switch up the cheese to your favorite to make this mashed potato gratin your own.

If you love this recipe as much as I do, please write a five-star review in the comment section below (or on Pinterest with the “tried it” button – you can now add pictures into reviews, too!), and be sure to help me share on facebook!

scoop of mashed potatoes with text "mashed potato gratin"

This creamy and fluffy Mashed Potato Gratin is perfect for using up leftover mashed potatoes, or make fresh, and is an elegant side dish for any occasion!

MORE EASY RECIPES

dish of mashed potatoes

Mashed Potato Gratin

Yield: 12 servings
Prep Time: 10 minutes
Cook Time: 15 minutes
Total Time: 25 minutes

Move over plain potato side dish and serve this delicious Mashed Potato Gratin! Creamy potatoes, mixed with cheese, and topped with a crispy, buttery panko topping.

Ingredients

  • 5 large Russet potatoes (appx 3 pounds)
  • 1/2 cup sour cream
  • 1/2 cup milk
  • 1 large egg (beaten)
  • 6 tablespoons butter (divided 4 tbsp + 2 tbsp)
  • 1 cup panko crumbs
  • 4 ounces cheese (Emmentaler is used this time)

Instructions

  1. Heat oven to 375F.
  2. Peel and dice the potatoes. Place in a large pot and cover with cold water. Add 2 teaspoons salt.
  3. Bring to boil over high heat and cook until the potatoes are fork tender. Drain and return potatoes to the pot.
  4. Gently mash the potatoes.
  5. Add the milk, sour cream, cheese, and 4 tablespoons of butter. Mix to combine.
  6. Season with salt and pepper as desired.
  7. Spray a 9x13 baking dish with cooking spray to prevent sticking.
  8. Spread the potato mixture in the prepared baking dish.
  9. In a small bowl, combine the panko with 2 tablespoons of melted butter. Mix until the panko is coated well.
  10. Sprinkle the buttered panko crumbs over the mashed potatoes.
  11. Bake at 375F for 15-20 minutes or until the potatoes are hot and the top is golden brown.
  12. Remove from the oven and serve warm.
  13. Enjoy!

Notes

*If you love this recipe as much as I do, please leave me a comment and rate it 5 stars. Thank you!

Recommended Products

This post may contain affiliate links. As an Amazon Associate, I earn from qualifying purchases. Read my disclosure policy here.

Nutrition Information:
Yield: 12 Serving Size: 1
Amount Per Serving: Calories: 275Total Fat: 12gSaturated Fat: 7gTrans Fat: 0gUnsaturated Fat: 4gCholesterol: 47mgSodium: 204mgCarbohydrates: 34gFiber: 3gSugar: 3gProtein: 8g

This nutrition information was generated via a third party, Nutritionix, and can not be held liable for any discrepancies in the information provided.

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8 Comments

  1. What a fun twist on potato au gratin!

  2. I’m not waiting for the holidays to make this!! YUM

  3. This looks so perfect and delicious. I love how creamy it is and the topping is perfect and crusty.

  4. I always make way too many mashed potatoes and this is a great way to repurpose them!

  5. This is super delicious and this will be loved in our home. This is a great holiday side!

  6. The crunchy top on this is amazing!

  7. This is a keeper recipe, perfect cheesy potatoes and my boys went back for more.

  8. Next time I make mashed potatoes I’m making a double batch so I can make this. All the potato cheesy goodness is a must for me.

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