Cheesy Mashed Potato Gratin with Sage Butter

Oh. My. Gosh.

I have found my newest favorite way to eat potatoes. And that’s coming from a full-on-spud-obsessed Irish girl who could eat the humble potato at all meals until the end of her days.

Or, for a far less dramatic explanation: that’s really saying something.

I love potatoes every which way you can give them to me. French fries still reign supreme as my favorite food of all time. Yes, really. I love them more than pasta, ice cream, cookies, pizza, and all the other wonderful treats out there. They are THE BEST.

There is nothing better than a piping-hot plate of fresh fries. Crispy and fluffy at the same time. With lots of salt. And perhaps an aioli for dipping? Heck, ketchup is way up there on the list of my favorite fry dips. Sometimes nothing else will do.

Today’s cheesy and creamy potato side dish is inching closer and closer to the top of my fave potato recipes. This one is really something special, guys. And it BELONGS on your holiday dinner table!

Don’t let the humble potato be overlooked. It works perfectly with most things, and these mascarpone mashed potatoes are no exception. Creamy, soft, and buttery…these mashed potatoes are the stuff of dreams.

After the potatoes are boiled and mashed to a dreamy consistency, I get really wild and stir in lots of mozzarella cheese (for that to-die-for gooey effect) and pile the potatoes into a baking dish where they get topped off with crispy breadcrumbs and, wait for it, a healthy, gorgeous drizzle of sage-infused butter!

Gah. There isn’t anything I want more than this right now.

I love this idea of transforming mashed potatoes (which really need to be served immediately after being made) into a low-key but still over the top side dish that can be made completely ahead and baked off just before serving. You still get that classic fluffy mashed potato, but it’s just been amped up a bit with the cheese, breadcrumbs, and sage butter.

People will lose their minds over these potatoes. I guarantee it. In fact, I’m fairly certain that my purist potato loving father would be on board with this version of mashed potatoes. Come the holidays, he MUST have an obscene pile of mashed taters on his plate (preferably with a hot lava gravy trail spilling over on all sides) in order to be happy. While he might scoff at these elevated mashed potatoes at first (no gravy! oh the horror!), I think he would soon join me in the swooning after one bite.

I mean, just look at that cheesy spoonful!

I’m dead.

Don’t bother reviving me. I want to remain her, face planted into my pile of luscious potatoes. Thank you.

Cheesy Mashed Potato Gratin with Sage Butter

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★★★★★

5 from 1 review

• Yield: 6-8 side servings 1x

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Ingredients

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• 4 lb potatoes, peeled and diced (I prefer Yukon Gold)
• 2 teaspoons kosher salt, for cooking the potatoes
• 6 tablespoons unsalted butter
• ⅓ cup fresh sage leaves, plus more for garnish
• 4 oz mascarpone cheese, at room temperature
• 1 cup milk
• 1 cup grated mozzarella cheese
• 1 cup panko breadcrumbs
• Salt and pepper, to taste

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Instructions

1. Preheat the oven to 400°F and butter a 2-QT baking dish.
2. Place the potatoes in a large pot and fill with enough cold water so the potatoes are covered by at least an inch of water. Add 2 teaspoons of kosher salt to the pot.
3. Bring the potatoes and water to a boil over medium-high heat and then cook for 12-15 minutes, or until they are very tender.
4. While the potatoes are cooking, heat the butter in a small saucepan over medium heat. Once it is melted, add in the sage leaves. Reduce the heat to low and cook until the butter is bubbly and lightly brown and the sage leaves are crisp, about 5 minutes. Remove from the heat and set aside.
5. Drain the potatoes and return them to the pot. Start mashing the potatoes with a potato masher.
6. Pour in roughly 4 tablespoons of the sage butter (reserve the rest, along with the crispy sage leaves, for serving), the mascarpone cheese, and the milk.
7. Keep mashing and stirring the mixture until the potatoes are fluffy and creamy and all of the ingredients have been well incorporated. Fold in the mozzarella cheese. Season the potatoes with salt and pepper, to taste.
8. Transfer the potatoes to the prepared baking dish, smooth out the top, and then sprinkle on the panko breadcrumbs.
9. Place the baking dish in the oven and bake, uncovered, for 15-20 minutes or until everything is bubbly and the top is golden brown.
10. Remove, allow to cool slightly, and then serve hot. Drizzle the remaining sage butter over top just before serving. Garnish with the crispy sage leaves.

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