There are various different forms of cakes, but the basic components are flour, eggs and sugar. Added to this, butter or other forms of fat provide moistness.
Varieties include: butter cake, sponge cake, Genoise sponge and yeast cake.
A butter cake is made up from butter and sugar creamed together and then the eggs and flour are folded in.
A sponge cake is made up by whipping eggs and sugar and folding in the flour.
Genoise adds to the above recipe some clarified butter.
Yeast cakes are closer to a bread than a cake, such as a Stollen.