1.Preheat oven to 180°C grease and line three 20cm x 30cm lamington pans.
2.Make cakes according to directions on packets, divide mixture between prepared pans; bake in moderate oven about 35 minutes. Stand cakes in pans 5 minutes; turn onto wire racks to cool. Using serrated knife, level cake tops so they are the same height.
3.Turn cakes cut-side down. Using picture as a guide, cut out seal and ball shape from cake; discard remaining cake. Assemble cakes on 62 x 85cm prepared rectangular board, cut-side down.
4.To make butter cream, beat butter until white as possible, gradually beat in half the sifted icing sugar then milk, then remaining icing sugar. Beat until smooth.
5.Tint two-thirds of the butter cream with black colouring to make grey; spread all over seal. Using fork, mark seal’s skin. Tint a quarter of the remaining butter cream with orange colouring, a quarter with blue colouring, a quarter with green colouring and the remaining butter cream with pink colouring.
6.Using toothpicks, score ball markings onto cake. Spread tinted butter creams over top and sides of each ball quadrant.
7.Cut licorice strap into thin strips; position on cake for outline of seal, ball, whiskers and eyelashes. Cut small piece of the licorice for the nose and eye.
8.Trim marshmallow to make pupil and tip of nose; use a little butter cream to attach to licorice. Cut a thin strip of licorice into tiny pieces and place around whiskers.