Shortening has been a baking staple since the early 1900s, when the Crisco company introduced solidified vegetable oil as an economical alternative to lard and butter. Shortening adds moistness, but it also adds fat to your baked goodies. You can replace some of the shortening with yogurt, which is low- or nonfat, but the flavor and texture of the end result will be different.
Substitutions Not Always Equal
Home cooks of today have access to a variety of yogurt products that bakers of past generations could only dream of. At the time of its invention, shortening was a convenient alternative and could be substituted cup for cup for butter or lard, with only minor changes in the liquid content. Substituting yogurt for some of the butter in a quick bread or brownie recipe is commonplace; however, the conversion doesn't extend to shortening in the same manner.
Purpose of Shortening
Shortening is 100 percent fat. If your recipe specifically calls for shortening, it probably needs those fat molecules for a particular purpose. In cakes, fat contributes to the amount of spread and eventual form. When you're making biscuits or pie crust, shortening "shortens" the gluten fibers, resulting in a light, flaky product instead of a hard, dense dough.
Advantages of Yogurt
One cup of nonfat yogurt, which contains one-third of the daily recommended calcium intake, is high in protein, so including it in your baked goods is a good nutritional option. Yogurt also has less fat and calories than shortening, making it a wise choice for weight-conscious bakers.
You can substitute half of the shortening in a recipe with 3/4 the amount of yogurt. For example, if your brownie recipe calls for 2 cups of shortening, use one cup shortening plus 3/4-cup yogurt. When a recipe calls for shortening or oil, replace half of the oil with 3/4 the amount of yogurt. For instance, instead of 1 cup oil, use 1/2-cup oil and 1/4-cup plus 2 tablespoons yogurt. If your recipe calls for 1 cup of shortening, use 1/2-cup shortening and 1/4 plus 2 tablespoons of yogurt.