Low fat does not have to mean low flavor. Solid fats such as butter or shortening in baked goods add flavor and contribute to the texture of the product, but these ingredients also increase the fat level in the food. Applesauce successfully replaces the butter in cakes and cookies without significantly affecting the final product if you make some adjustments to the recipe.
Replace all of the butter with an equal amount of unsweetened applesauce for the lowest-fat product. For instance, if your recipe calls for 1/2 cup butter, use 1/2 cup applesauce. To maximize taste and texture while still decreasing fat considerably, leave in about a quarter of the butter and substitute out the remainder. For instance, if a recipe calls for 1 cup of butter, use 1/4 cup butter and 3/4 cup applesauce.
Add the applesauce to the liquid ingredients such as the milk or eggs in the recipe.
Reduce the baking time by 25 percent. For instance, if a cake must bake for 60 minutes, check the cake after 45 minutes.