You can make fluffy, creamy mashed potatoes without butter by choosing the right variety of potato, using proper technique and making smart substitutions.
Select Potatoes Carefully
Potato cultivars vary in their starch content. High starch potatoes such as the common russet potato, Yukon gold potato, Caribe potato and purple potato are very starchy and therefore hold their structure well when mashed, beaten and whipped.
Less starchy varieties are still delicious, but will break down and give a creamier, denser texture. For buttery color and texture without using butter, use Yukon Gold or Yellow Finn.
To achieve fluffy and creamy potatoes, choose a high starch potato and add substitute finishing ingredients in place of butter.
Buy one potato for each serving.
How to Make a Fluffy Mash
To start your mash, peel and quarter the potatoes, and place in a large pot with just enough water to cover. Bring to a boil and simmer uncovered until the potatoes are fork tender but not falling apart, about 15 minutes. Don't cook the potatoes too long or they will absorb too much water and become waterlogged and heavy.
Immediately drain the potatoes in a colander over a bowl or pot, reserving the cooking liquid. Let them cool slightly (you want them to evaporate some of the cooking water), and then thoroughly mash them in a large bowl with a large fork or potato masher. For even smoother texture, give them a quick whirl with a handheld mixer. But don't overprocess the potatoes, or the starches will break down and you'll lose that light, fluffy texture.
If the potatoes seem dry, add a spoonful or two of the cooking liquid and gently fold it in.
Adding Dairy and Butter Substitutes
If it's butter you want to avoid, you can add a small quantity of margarine or a spreadable blend of healthy oils.
If you have no objection to dairy, you can add sour cream, whole milk, heavy cream, cream cheese, grated hard cheeses or crumbled blue cheese. Limit your additions to about ½ cup per four potatoes. Add just before beating, or fold the addition in gently with a wooden spoon to avoid breaking down the starches.
Healthy Nondairy Substitutes
For nondairy additions that will convey a sweet, fatty flavor, try adding homemade chicken broth, creamy tofu, cold pressed nut oils such as almond oil or walnut oil, or oil from a jar of sundried tomatoes.
Other additions that add interesting flavor and richness include sliced, grilled sweet peppers; yellow spices like saffron and turmeric; or sauteed, chopped portobello mushrooms.