The amount of butter needed to make a chocolate cake from scratch depends on the desired texture of the cake, but most recipes that contain butter require 4 to 6 tablespoons. Some chocolate cake recipes do not call for butter at all in the cake mixture.
The butter needs to be softened or melted, depending on the recipe. A traditional Hershey's chocolate cake contains vegetable oil and milk as the fattening agents instead of butter. Buttermilk is another alternative to butter. Something to consider when quantifying ingredients is that many frosting recipes also contain butter, even when the cake recipe itself does not.