Almost every baking recipe calls for some kind of fat—whether that's oil, shortening or butter—to be added to retain the moisture, flavor and texture of the baked goods. While oil and shortening are full fat, butter has a slight amount of water. These ingredients may seem interchangeable, but the end result may be slightly different. Butter adds a creamier flavor to any recipe and, in a pinch, can easily be used in place of shortening.
Chill the butter before use so that it retains a solid consistency similar to shortening.
Measure out the same amount of butter as the amount of shortening called for in the recipe. (Use 1 cup butter for 1 cup shortening.)
If the butter is salted, remove 1/2 teaspoon of salt from the recipe for every 1 cup of butter used. (If 1/2 cup salted butter is substituted for 1/2 cup shortening, remove 1/4 teaspoon salt from the recipe.)
If the finished product doesn't turn out as moist as you wanted it, add another 1/8 cup butter in addition to the 1:1 ratio. (Use 1 1/8 cup butter for every 1 cup shortening called for in the recipe.)