Choose a substitute based on the recipe’s job for butter: structure (cookies/scones), flavor (sauces), or browning (pan cooking).
Match fat behavior: for most baking, start with 1:1 swaps that melt and cream like butter (salted butter, cultured unsalted butter, shortening, margarine-sticks).
Control salt: if using salted butter, reduce any added salt in the recipe (especially for bread dough, frostings, and simple batter recipes).
If the substitute is wetter or softer (yogurt, oil blend), adjust by chilling (for margarine) or thickening (add flour in small increments for batters).
Taste-and-test: cook a small portion first (or do a quick bake test) to confirm browning and flavor before committing to the full batch.