Several types of fat are used in cookie baking. Butter is often
used because it gives good baking results and excellent flavor.
Salted and unsalted butter may be used interchangeably. If you
use unsalted butter for cookie baking, you may want to slightly
increase the amount of salt in the recipe. Use the convenient
marks on the butter wrapper for measuring. If you choose to use
margarine for cookie baking, use one that contains at least 80
percent vegetable oil. If you can't tell from the front of the
margarine package, check the nutrition label. The margarine
should have 100 calories per tablespoon. Those margarines with
less than 80 percent vegetable oil have a higher water content
and can result in tough cookies that spread excessively, stick
to the pan, and don't brown as well. Margarines also have
convenient measurements on the wrappers. Shortening is sometimes
called for in cookie recipes. Shortening now comes packaged in
sticks which are marked with measurements, just like butter or
margarine. Shorteni