Shortening is any type of fat that is solid at room temperature. It’s used to prevent the formation of a gluten matrix in baked goods, allowing for the creation of non-elastic pastries like cakes. Lard, hydrogenated solidified oils, and even butter can be used as shortening. However, in the modern kitchen, the word “shortening” refers to hydrogenated oils, such as vegetable shortening.
Vegetable shortening is also used in baked goods to keep them soft after baking.