Mashed Potato Gratin

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.

Mashed Potato Gratin

When I think of mashed potatoes, I think of the standard side dish that everyone loves. But sometimes you want something different without getting too fancy or blowing out the budget.

That’s where this casserole comes it. You can even make it with store-bought mashed potatoes to save more time.

Make it ahead of time, the crispy topping is yummy, it’s a great way to use up leftover mashed potatoes, and freezes beautifully!

Check out my creamed potatoes which are also super easy to make, and these million dollar mashed potatoes you can make in the crock pot.

Ingredients Needed

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 – Use a large size egg. Bring it to room temperature before beating.

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How to Make Mashed Potato Gratin

First: 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.

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

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

Fourth: 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 instructions, please see the recipe card at the end of this post.

How long does it last?

Store any leftover mashed potato gratin in the refrigerator, in an airtight container, for up to 4 days.

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.

Can I freeze it?

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.

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. Thanks!

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!

Here are more Side Dish recipes:

• 1 Hour Soft and Buttery Dinner Rolls from Hezzi-D’s Books and Cooks
• Apple Stuffing Muffin Cups from Blogghetti
• Braised Red Cabbage with Cranberry and Juniper from Palatable Pastime
• Carrot Peanut Slaw from A Kitchen Hoor’s Adventures
• Creamy Kale and Corn from Magical Ingredients
• Garlic Parmesan Green Beans from Cookaholic Wife
• Mashed Sweet Potatoes with Bacon & Chives from Sweet Beginnings
• Roasted Brussel Sprouts with Bacon, Pecans, and Cranberries from Jen Around the World
• Roasted Butternut Squash & Rice Salad from Jolene’s Recipe Journal
• Skillet Corn from Devour Dinner
• Whole Roasted Squash from Art of Natural Living

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