The main role fat plays in baking is to coat and weaken gluten bonds which results in a more tender baked good. They help to retain air pockets and carbon dioxide that will be released during baking. Fats come in the form of solids and liquids and are sometimes referred to as tenderizers.

Sometimes referred to as plastic fat, solid fat examples are: butter, tallow, lard, and shortening. They remain solid at room temperature and can be melted by warming or heating. In baked goods, solid fats are often whipped or creamed which creates air bubbles within the fat resulting in a light texture. Solid fats can also be used as a separator in many recipes (biscuits and croissants) to create delightfully flaky layers. Butter is used in baking for its superior flavor over other fats. It can add tenderness, structure, flakiness, and a rich, delicious flavor to baked goods. It contains good saturated fats, trace minerals, healthy fatty acids, and provides Vitamin A, D, E, and K. 

The definition of shortening is any fat that is solid at room temperature. Examples includes butter, tallow, lard, and vegetable shortening. The name ‘shortening’ comes from the fact that when solid fat is combined with flour it prevents gluten from forming, or ‘shortens’ the gluten strands.