Can whipped butter be substituted for stick butter in recipes for baked goods?
Whipped butter is made by incorporating air into butter. Manufacturers do this to increase the butter’s spreadability, especially for slathering on toast. Adding air increases the volume of the butter, not the weight. In other words, a 4-ounce stick of butter measures 1/2 cup in volume, and 4 ounces of whipped butter measures 1 cup. We decided to compare unsalted whipped butter and unsalted stick butter in our Glazed Butter Cookies, Classic Pound Cake, and Classic Vanilla Buttercream.
Tasters found the cookies to be nearly identical and even slightly preferred the whipped-butter version for its “crispier” and “flakier” texture. The same held true for the pound cake. Although the butter for each cake was creamed for exactly the same time—5 minutes—some tasters deemed the cake made with whipped butter to be “lighter,” “fluffier,” and “more tender.” The buttercream was a different story. While the stick butter produced a fluffy, off-white frosting, the whipped-butter frosting was foamy, with an intense yellow color and a “plasticlike” texture.
So-unsalted whipped butter makes a fine substitute for unsalted stick butter in baked goods, but do not make the swap in uncooked applications, such as frosting. And remember to make the substitutions based on weight, not volume. A standard tub of whipped butter weighs 8 ounces, equal to two sticks of butter.