1.Preheat oven to 180°C; grease and line 8cm x 26cm bar cake pan and 20cm ring pan.
2.Make cake according to directions on packet; divide cake mixture between pans so both mixtures are the same depth. Bake about 25 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. Cut bar cake into three pieces. Assemble cake pieces on 30 x 49cm prepared rectangular board, cut-side down, to form the number nine; discard remaining cake.
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 butter cream with green colouring; spread three-quarters of the butter cream over cake.
6.Tint remaining butter cream with more colouring to make a deeper green. Spoon into piping bag fitted with 4mm plain nozzle; pipe vine and tendrils onto cake.
7.Position chocolate ladybirds and spearmint leaves on cake, using picture as a guide.