Horseradish Mashed Potatoes

Inside: Why these mashed potatoes belong next to prime rib — and the horseradish cheese that makes them shine.

Horseradish mashed potatoes are a rich, flavorful upgrade on the classic—and one of the best sides for prime rib. A compound horseradish cream cheese melts into the potatoes for extra creaminess and a clean, noticeable bite, while butter and whole milk keep the texture smooth and luxurious. Easy to make and perfect with prime rib or beef tenderloin, this is a holiday side that holds its own.

A bowl of mashed potatoes with chives on top.

When the holidays roll around, and you’re serving big, impressive roasts like fork-tender prime rib or beef tenderloin, your potato recipe has an important job to do. It should support the star of the table, adding richness and interest without competing for attention. That’s exactly where these horseradish mashed potatoes shine—familiar, comforting, and just elevated enough to feel special.

The secret is the simple horseradish cream cheese: a blend of cream cheese, prepared horseradish, Worcestershire sauce, and minced chives. I use this spread for cold roast beef sandwiches instead of sliced deli-cheeses because it actually adds flavor and a creaminess you won’t get with a slice of Swiss.

When stirred into hot, fluffy potatoes, it melts effortlessly, infusing them with creamy texture and a gently perked-up flavor that complements beef beautifully. If your roast is served with au jus or a creamy horseradish sauce, the combination is even better, tying everything on the plate together.

Other side dishes that add exponentially without detracting from the centerpiece include my Creamed Spinach, Balsamic Mushrooms or my simple Garlic Green Beans Recipe.

Why this recipe works:

Plush potatoes–Mashing the potatoes with a masher or ricer, prevents the spuds from becoming over-worked and gluey for a creamy texture that only gets smoother with the flavored cream cheese.
Built-in creaminess without heaviness – Unlike shredded hard cheeses, cream cheese melts smoothly into the hot potatoes, while butter and whole milk create a velvety texture.
Designed to complement beef, not compete with it – The subtle horseradish heat boosts the flavor of prime rib or beef tenderloin and pairs naturally with the obvious accompaniments, making these mashed potatoes with horseradish the obvious choice.

Ingredients:

White Potatoes – You can also use russet potatoes or Yukon Gold potatoes; both mash up smooth and creamy. Russets tend to be fluffier, while Yukon Golds are creamier, adding a naturally buttery flavor and a pale color.
Horseradish Cheese – A simple compound cheese that melts into the potatoes, adding richness and a clean horseradish bite without overwhelming heat.
Unsalted Butter – Enhances flavor and silkiness, helping the potatoes feel rich and indulgent.
Whole milk – Loosens the mash and creates a smooth, cohesive texture without thinning it out.
Kosher salt – Or fine sea salt; essential for seasoning the potatoes properly. If you use Kosher salt, Diamond Crystal is my preferred brand, because it’s less salty by volume. With Morton’s you need to reduce the amount used by about ⅓.
Black pepper – Fresh ground will give the best flavor.
Chives (optional) – Provide a mild onion note and a fresh pop of color right at the finish.

Step-by-step instructions:

Peel the potatoes. (I love this cheap Zyliss y-peeler; affiliate link).

2. Cut the potatoes into 1″ pieces.

3. Transfer the potatoes to a 3-quart saucepan and cover them with cold water. Bring the pot to a boil, reduce the heat to medium-low, and simmer for 10-12 minutes or until tender.

Smash the potatoes with a masher or potato ricer.

4. Mash the potatoes with a potato masher or ricer.

5. Add the horseradish cheese to the potatoes and mix in until the cheese has blended evenly into the potatoes.

6. Warm the milk and melt the butter together. You can do this on the stovetop in a small saucepan, or combine them in a microwave-safe container and heat in 30-second bursts until the butter melts, then stir to combine.

Add the milk and butter a little at a time.

7. Season with salt and pepper and add the hot milk and butter a little at a time to the horseradish mashed potatoes, stirring after each addition until you have the consistency you want.

8. You can taste for seasonings and adjust as needed.

Pro-Tips:

You can tell if the potatoes are cooked through by poking the center of one with a sharp paring knife and lifting it from the pot. If the potato slides off the knife, it’s done. If it stays put, it needs more time.
A potato masher does a decent job of breaking down the spuds, but can leave a few lumps (fine, so long as you don’t mind), whereas a potato ricer does a foolproof job of pureeing, so there are no lumps. I don’t recommend using a hand mixer, as it’s easy to overbeat, which releases more starch and makes the spuds gluey.

Swaps and Variations:

Like sour cream in your potatoes? Swap the horseradish cheese for a half cup of full fat sour cream and 3-4 tablespoons of horseradish. Mix to blend, then combine with the smashed spuds.
Don’t have chives? Garnish your potatoes with chopped parsley.

FAQs

How do restaurants make their mashed potatoes taste so good?

I was interviewed for this Food Republic article on why restaurant mashed potatoes are so good—the short answer: Butter and cream, plus tried-and-true techniques for mashing.

Should you use milk or cream in mashed potatoes?

It’s up to you. Whole milk does a good job of adding a creamy consistency, but half-and-half or cream makes them even more decadent.

Make ahead:

You can make horseradish mashed potatoes an hour or so before serving and keep them warm by adding an inch of water to a saucepan and boiling, then reducing the heat to low. Fit the bowl of potatoes in the pan, so it sits above the water and cover with plastic wrap. The potatoes will stay warm until you serve.
Check the water level regularly so it doesn’t evaporate completely and scorch the pot.

Storage:

Store leftover horseradish mashed potatoes in an airtight container in the fridge for 3-5 days.

Reheating:

Reheat in the microwave in 30-45 second bursts.
To bring back the creamy consistency, add a bit more hot milk and melted butter (¼-½ cup), stirring until it’s the texture you like.

Freezing:

Freeze horseradish mashed potatoes in zip-top freezer bags; fill the bags, remove excess air pockets and seal. Lay the bag flat on its side to freeze solid.
Defrost before reheating.

Whether you want mashed potatoes for prime rib or to serve with a grocery store rotisserie chicken, these horseradish mashed potatoes are a guaranteed winner.

They are smooth and creamy with a noticeable but not overpowering horseradish flavor. The cream cheese ensures a lush texture. My tasters couldn’t get enough – and I think you’ll agree that while this mashed potato recipe is perfect for the holidays, they’re simple enough for everyday. Don’t wait for Thanksgiving or Christmas to make them.

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