Homemade cookies come out flat due to soft dough or warm tools and ingredients. The flat nature is caused by the dough heating up and spreading too fast during the baking process. Because butter melts quickly, home chefs can use shortening or oil instead to uphold the shape and texture.
Chill the dough before spooning the cookies onto the pan or chilling pans in the refrigerator also helps balance the spread of the cookies. Opting for parchment when lining a baking sheet instead of greasing the pan with additional butter can also help, as can allowing the cookies to form naturally in small dollops rather than forcing them into a circular shape.