This is a version of a recipe that I did for Oprah’s magazine. I like to use yogurt instead of butter because its acidity heightens the other flavors. My preference is for full-fat Greek-style yogurt, but any unsweetened plain yogurt will do. If you can find labne, a Middle Eastern-style yogurt, that’s another great choice.
Put the potatoes and garlic in a pan that is big enough to hold them, but not overly large. Add enough water to barely cover and season generously with salt. (Potatoes absorb water as they cook, so if the water is seasoned, the potatoes will taste great throughout. If you try to season them at the end, it often doesn’t produce the same results. Also, the potatoes’ flavor is water-soluble, so the more water you use to cook them, the weaker the taste will be. Try tasting the cooking water when you strain it off. Tastes like potatoes, right? You are pouring flavor down the drain.)
Bring the water to a boil, then reduce the heat to a simmer and cook until the potatoes are soft and just beginning to fall apart. Drain, reserving some of the cooking water. Add the yogurt to the potatoes and mash together. If they are a little too thick, add the reserved cooking water a few tablespoons at a time until it reaches your desired consistency.