Butter

Butter: Nothing beats the flavor, texture, and richness that butter adds to baked goods. For most recipes, we recommend using butter rather than margarine.

What doesn't make a difference is whether you use salted or unsalted butter (although if you use unsalted butter, you may want to increase the amount of salt in the recipe). 

Margarine: Margarine, made from vegetable oil or animal fat, was developed in the late 1800s as a substitute for butter.

Shortening: Shortening is a solid fat that has been made from vegetable oils. It's often used for tender, flaky piecrusts and biscuits.

It comes packaged in sticks marked conveniently with tablespoon and cup measurements and in bulk tubs. Shortening can be stored at room temperature for up to a year. Plain and butter-flavored types are available; use whichever you prefer.

Cooking oils, flavored oils:  Mildly flavored vegetable oils generally are made from corn, soybeans, sunflower seeds, or peanuts, and have a pale color. Nut oils, such as walnut oil, have a pronounced nutty flavor and can be darker in color. Olive oil is used primarily in baking recipes for focaccia, pizza doughs, breads, and the occasional cake.

Margarine and stick spreads for butter: For best results in baked products, choose a margarine or a stick spread that contains at least 80 percent vegetable oil. Do not use an "extra light" spread that contains only about 40 percent vegetable oil.

A recipe will usually give a margarine option. If there is no margarine option it is because after testing with it, it was determined that butter makes a far superior product.

Oils for solid fats: For baking, cooking oils and flavored oils cannot be used interchangeably with solid fats. Oils are unable to hold air when beaten. Substituting an oil for a solid fat, therefore, could result in a vastly different end product in texture and taste.