Fat – not dairy per se – makes food creamy, but dairy-based foods tend to have a lot of fat and therefore creaminess. Butter, heavy cream, fresh cheese, half and half, sour cream, crème fraîche – if it has full-fat dairy, it adds creaminess. That said, vegans and lactose-averse foodies have several alternatives to dairy when making mashed potatoes, alternatives that contribute their own unique flavor profiles. Nondairy ingredients can add such unique flavor and textural elements that even mashed potato traditionalists love the result.
Superb mashed potatoes don't owe their creaminess to dairy alone. Creamy mash starts with the right potatoes, and in this case, right means starchy, low-moisture varieties.
Start With Starchy
Starchy spuds like Yukon gold and russet potatoes absorb fat and fluff up far better than waxy varieties like new potatoes and Carolinas. You can use all Yukon gold, all russets or a 50-50 combination of both. Yukon golds have a more pronounced potato taste than russets, but the latter have a touch more creaminess – you get the best of both with a mix.
Whole Versus Cubed
Boil the potatoes whole with the peel on. Peeled, cubed potatoes absorb more water than whole potatoes, and more water goes against the creaminess goal. When the potatoes finish cooking, rub the peels off by using a towel.
Oil adds just as much creaminess as butter and whole milk – more so, in fact, as oil doesn't contain water – but doesn't produce the same visual aesthetic, and thus doesn't give the perception of a creamy ingredient. But in a blind taste test, you'd be hard-pressed to tell the difference in mouthfeel between mash made with dairy or made with oil. And with the plethora of flavored oils out there, you have a lot of latitude for creativity. Mashed potatoes with black truffle oil, anyone? When substituting oil for dairy in mashed potatoes, use 1 tablespoon of olive, vegetable or truffle oil per pound of potatoes.
Thanks to equal parts clever marketing and demand, nondairy milks created and populated their own market niche and aren't going anywhere: soy milk, almond milk, hemp milk, coconut milk, oat milk, hazelnut milk – and that's just what you can find in stores! A lot of nondairy milks don't have as much fat as butter and milk, and therefore not as much creaminess. However, the creaminess, and flavor, they contribute is not to be discounted.
You can go with your personal tastes when using a nut milk or other nondairy milk in mash, but for something that not only replicates the creamy taste of dairy but adds a creamy texture too, go with cashew milk. Its flavor lingers in the background, so it doesn't intrude on the hearty potato taste, but it smooths out the whole dish. Nondairy milks vary in consistency, so when making mash with nondairy milk, start with 1 tablespoon and add more to taste as needed.
Velouté is simply chicken or vegetable stock thickened with roux. Roux is typically made with equal parts butter and flour, but any fat works; rendered bacon fat, schmaltz and oil all do the trick. The benefits of using velouté in place of dairy is twofold: You get a unique creaminess that can only come from roux and the flavor of the stock you choose. To cream-ify your mash with velouté, add stir in 1 to 2 tablespoons of vegetable or chicken velouté and add more to taste, if desired.
Egg yolks are on par with heavy cream when it comes to thickening ability. In fact, the elegant egg yolk-based thickener, the classic French liaison, is used to thicken the creamiest cream-based soups and sauces. To make a liaison for use in mash, mix 1 large pasteurized egg yolk with 1 tablespoon of nondairy milk per 1 pound of potatoes and stir in while hot.
Use a ricer to mash the potatoes instead of a potato masher. Ricers produce a fluffier, airier mash than food mills and potato mashers.
Never use a food processor or stand mixer to mash or whip potatoes. The rapid manipulation of the starch molecules causes them to gelatinize and take on a glue-like consistency.
If you can't eat dairy because of digestive issues, try thickening your mashed potatoes with lactose-free milk, cream or butter; you get all the creaminess without the tummy troubles.