Cookies are a class of baked good, overlapping somewhat with cakes and pastries. The term "cookie" means "little cake", and it encompasses a wide variety of baked goods, including those called biscuits in British English.
Cookies can have a wide variety of characteristics—the main thing all cookies have in common is their overall small size and a tendency to be eaten with the hands. Otherwise, they come in a range of sizes, textures, shapes, flavors, and more.
The spread of a cookie refers to how much the dough spreads out horizontally during baking. High air content (from leavening or long creaming), high sugar content, high moisture, low oven temperature, and greased pans all contribute to increased cookie spread. High-protein flour, high gluten development, high temperature, low moisture, and cold dough all contribute to reduced overall spread. Butter will cause more spread than shortening because of the small amount of water present in butter. Confectioner's sugar will reduce spread compared to granulated sugar due to its moisture-absorbing starch content.
A variety of factors can contribute to a cookie's chewiness, including a high sugar-and-liquid to fat ratio, a high egg content, and a high-protein flour.
The main cause of crispness in a cookie is very low moisture. This can be achieved by simply including little moisture in the initial dough, using high sugar and fat contents, baking for long enough to evaporate the moisture, and shaping the cookies thinly in order to more quickly achieve the latter.
Cookies with a higher sugar content are generally moister than those without, as a result of sugar's hygroscopic properties. Eggs also contribute moisture.
Increased browning can be achieved, if desired, by longer time in the oven, higher oven temperature, and a higher-protein-content flour.
Sliced cookies, sometimes called icebox cookies, are made by shaping the dough into a log, chilling until firm, and slicing off individual cookies.
Drop or scoop cookies are made by portioning cookies directly onto the baking sheet using spoons or a scoop.
Molded cookies are made by shaping the cookie dough with a mold, stamp, or your hands.
Bar or sheet cookies are baked in one large sheet that is cut into individual pieces after baking. This can include brownies, pecan bars, some varieties of shortbread, and British flapjacks.
Tuiles, unlike other cookies, are made with a batter instead of a dough. The batter is spread on a silicone baking mat before baking to yield a very thin, crisp cookie
These cookies are made by baking a large mass of dough, slicing it into individual cookies, and baking a second time. This produces a very dry cookie and includes biscotti and mandelbrot.
Sandwich cookies are, as the name implies, made by sandwiching a filling between two cookies. These include macarons, oreos, alfajores, linzer cookies, and more.
Chocolate chip drop cookies
Stamping out cookies
The result of a cookie stamp
Langues de chat
Tuile cookies shaped into cigars