1.Preheat oven to 160°C. Line muffin pans with paper cases.
2.Make cake according to directions on packet. Drop rounded teaspoons of mixture into each paper case. Bake 15 minutes. Turn cakes, top-side up, onto wire rack to cool.
3.To make butter cream, beat butter in a small bowl with an electric mixer. Gradually beat in half the icing sugar and beat until as white as possible. Add milk and continue beating, then add remaining icing sugar. Beat until a smooth, spreadable consistency.
4.Spread butter cream over tops of cakes. Using picture as a guide, position letters and decorations on cakes.