Differences and Similarities

• Butter and shortening are both fats used in baking, but the similarities end there. Butter is made from cream, while shortening is made from vegetable, canola or soy oil that's been processed to thicken it. Butter is 80 percent fat and contains water. It melts at temperatures between 86 and 96 degrees Fahrenheit, and it is soft and pliable at room temperature. Butter has a distinct sweet taste that adds flavor to cookies. Shortening is 100 percent fat and melts at 106 F. At room temperature, it is pliable but firmer than butter.

Soft Cookies

• For the softest cookies, shortening is the better choice. Because shortening has a high melting point, cookies hold their shape better and tend to remain softer. The fat in butter melts more quickly, so cookies made with them spread and become crisper unless the dough is chilled first. The water in butter also creates an emulsion when combined with sugar, eggs and flour. This water becomes steam as the cookies bake, creating air pockets in the cookie dough for cookies that are somewhat crispy and flaky. Cookies made with shortening are not only softer right out of the oven, but they also tend to stay softer longer.

Potential Pitfalls

• Shortening is the clear winner for the softest cookies, but it does have a few negative characteristics. Most notably, shortening is flavorless and odorless. Cookies made with it lack the taste and aroma of cookies made with butter. Because shortening has such a high melting point, it may not melt in your mouth as you eat the cookies, causing a waxy film on the tongue and palate.

The Best of Both

• If you want the softness of shortening with the flavor of butter, you can have your cookie and eat it too. Try substituting shortening for part of the butter in a cookie recipe. You'll get soft cookies that still have a delicious buttery flavor. Consider the type of cookie you're making as well. Shortening is ideal for rolled or pressed cookies, because it keeps its shape better. For simple drop cookies, such as chocolate chip cookies, you may find that butter works better. Whether you use shortening or butter, remove the cookies from the oven a minute or two early for softer cookies. Cookies tend to become hard or stale within a day or two. Freeze them to keep them fresher and then thaw them at room temperature.