Butter is the fat element of liquid milk coalesced by agitation during the churning process. A product of ancient origin and of great importance in Eurasia and countries influenced by northern European foodways, it is an essential ingredient in many sweet foods, to which it gives structure and flavor. Butter is also boiled with sugar for certain confections, such as English toffee, in which sugar and the residual milk proteins contained in the butter combine in the Maillard reaction to produce delicious aromas and tastes.
