Pesto Buttermilk Mashed Potatoes

Pesto Buttermilk Mashed Potatoes Recipe

You may not believe it, but buttermilk mashed potatoes are just as fluffy as regular mashed potatoes made with heavy cream. The only difference is a pleasant tangy taste that the buttermilk imparts to the potatoes. To enhance the flavor of the mashed potatoes, I added some homemade Pecorino basil pesto. There is nothing subtle about this dish; it is absolutely bursting with color and flavor.

I was inspired to make this dish during our Christmas trip to Las Vegas. We went to our favorite eatery, "The Buffet at Bellagio". They served pesto mashed potatoes, but without buttermilk. It was so good I had to replicate it but of course, I wanted to add my own twist. I recently made a large batch of Pecorino basil pesto, so I thought it would be a good time to try my hand at the dish. I hope you like it!


Yields: 8 servings

3 pounds Russet potatoes (about 5 large)
1/3 cup milk, at room temperature
6 tablespoons butter, diced
1 cup buttermilk, at room temperature
2 teaspoons sea salt (or regular salt)
3/4 teaspoon white pepper, freshly ground
1/3 cup homemade Pecorino basil pesto (click on the link for the recipe), as needed
3 tablespoons Pecorino cheese


Boiling the potatoes:

Peel the potatoes, cut them into 2-inch chunks and place them in a large pot. Fill it with cold water until the potatoes are barely covered. It's important to start with cold water so the potatoes cook evenly. Bring to a boil, add 1 teaspoon of salt and reduce the heat to medium-high (if you cook the potatoes at a roaring boil, they might fall apart). Cook for about 20-25 minutes. The potatoes should be fork-tender. Drain the potatoes thoroughly and let them cool a little (do not rinse and let the liquid evaporate).

Mashed potatoes:

Once the potatoes are cool enough to handle and have dried thoroughly, return them to the pot over low heat (to ensure there is as little liquid as possible). Turn off the heat. Using a potato masher or a potato ricer, mash the potatoes. Add milk, butter and 3 tablespoons of pesto. Stir well, using a wooden spoon. Add the buttermilk until you reach the desired consistency. Season with salt and white pepper. Finish with the Pecorino cheese.

Top the potatoes with the remaining pesto and stir slightly to create a swirl. I served the mashed potatoes with a white fish but it would go great with beef or chicken as well.

Serve warm

Bon appétit!


I used left-over Pecorino basil pesto I had in the freezer. I always make extra to store in the freezer. If you have extra pesto, you can store it inan ice-cube tray and freeze it. I transfer the ice-cubes into bags that I vacuum-seal and place back in the freezer for future use. I think it's the best way to keep the same flavor without getting freezer burn. You can store the pesto in your freezer for up to 6 months or for 2 weeks in your refrigerator.

If you re-heat the mashed potatoes, it's preferable to use a double boiler. For an easy double boiler, place the mashed potatoes in a heat-proof bowl over a larger-sized saucepan filled with simmering water. I always like to add a little kitchen towel underneath the bowl. That way the bowl won't jiggle and there won't be any splatter of water in the mashed potatoes.

With leftover mashed potatoes, you can make a green-colored shepherd pie.


A big no-no  is to mash the potatoes in a food processor or a blender; the texture will be gooey and sticky and the result won't be good. The best way is to use a food mill, a potato masher or a potato ricer. You can also manually mash the potatoes using food service disposable gloves. And most important, do NOT over-work the mashed potatoes.

Ricer Picture

I finely chop a 3-inch chunk of Pecorino and place the morsels in a mini food processor to make Pecorino powder.

You could also serve the mashed potatoes with gravy on the side (click on the link for a vegetarian gravy recipe).

If you're a potato lover, check out my other potato recipes!

Published By: Jacqueline Pham on March 26, 2010.


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