What sour cream actually does in a recipe
Beyond its tangy flavor, sour cream's fat and acidity do real work — the fat adds moisture and richness that keeps baked goods tender, while the acidity gently reacts with baking soda for extra lift and can help tenderize gluten slightly. A good substitute needs to bring both qualities, not just a similar taste, which is why thinner or lower-fat swaps can leave a cake or muffin a little drier or less tender than the original recipe intended.
Which substitute to use when
Full-fat Greek yogurt is close enough in fat content and thickness to work almost anywhere sour cream is called for, baked or not. Buttermilk brings similar tang but is much thinner, so it's better whisked into a batter than served as a dollop on tacos or a baked potato. Cottage cheese needs to be blended completely smooth first, or it'll leave a grainy texture behind. Silken tofu is the only fully dairy-free option here — blending in a little lemon juice recreates sour cream's acidity, which plain tofu doesn't have on its own.
FAQ
Can I use plain regular (non-Greek) yogurt instead? Yes, but it's thinner and tangier than Greek yogurt — straining it through a cheesecloth-lined sieve for 20-30 minutes to remove excess whey gets it much closer to sour cream's actual thickness.
Will a substitute affect baking time? Not meaningfully at this scale — these swaps change moisture and richness slightly, not the recipe's overall liquid content enough to shift bake time in most cases.