In the United States and Canada, a cookie is a small, flat-baked treat, usually round, containing milk, flour, eggs, and sugar, etc. In most English-speaking countries outside North America, the most common word for this is biscuit

in many regions both terms are used, while in others the two words have different meanings—a cookie is a plain bun in Scotland, while in the United States a biscuit is a kind of quick bread similar to a scone.

Etymology

Its name derives from the Dutch word koekje or (informal) koekie which means little cake, and arrived in the English language through the Dutch in North America. It spread from American English to British English where biscuit is still the more general term.

Description

A general theory of cookies may be formulated this way. Despite its descent from cakes and other sweetened breads, the cookie in almost all its forms has abandoned water as a medium for cohesion. Water in cakes serves to make the base (in the case of cakes called "batter") as thin as possible, which allows the bubbles – responsible for a cake's fluffiness – to form better. In the cookie, the agent of cohesion has become some form of oil. Oils, whether they be in the form of butter, egg yolks, vegetable oils or lard are much more viscous than water and evaporate freely at a much higher temperature than water. Thus a cake made with butter or eggs instead of water is far denser after removal from the oven.

Oils in baked cakes do not behave as soda in the finished result. Rather than evaporating and thickening the mixture, they remain, saturating the bubbles of escaped gases from what little water there might have been in the eggs, if added, and the carbon dioxide released by heating the baking powder. This saturation produces the most texturally attractive feature of the cookie, and indeed all fried foods: crispness saturated with a moisture (namely oil) that does not sink into it.

History

Cookie-like hard wafers have existed for as long as baking is documented, in part because they deal with travel very well, but they were usually not sweet enough to be considered cookies, by modern standards1.

Cookies appear to have their origins in 7th century AD Persia, shortly after the use of sugar became relatively common in the region2. They spread to Europe through the Muslim conquest of Spain. By the 14th century, they were common in all levels of society, throughout Europe, from royal cuisine to street vendors.

With global travel becoming widespread at that time, cookies made a natural travel companion, a modernized equivalent of the travel cakes used throughout history. One of the most popular early cookies, which travelled especially well and became known on every continent by similar names, was the jumble, a relatively hard cookie made largely from nuts, sweetener, and water.