Preheat oven. Grease (and line) pan(s). Beat butter, extract and sugar in a small bowl with an electric mixer until light and fluffy. Beat eggs, one at a time. Stir in sifted flour and milk, in two batches. Bake as directed.

To marble a butter cake, place portions of cake mixture in 3 bowls then tint each with the desired colours. Drop spoonfuls of mixture into pan(s), alternating colours, then swirl together with a skewer for a marbled effect.