There are several main classes of cakes: butter/oil cakes, foam/sponge cakes, and low- or no-flour cakes. Butter cakes are the most common and use oil or butter, creating a moist and tender texture. Pound cakes contain equal parts butter, sugar, eggs, and flour while layer cakes are lighter. Foam cakes like sponge cakes rely on whipped eggs for volume rather than fat. Low- or no-flour cakes either contain little flour or are unbaked, including cheesecakes, flourless chocolate cakes, and mousse cakes.