1.Preheat oven to 180°C (160°C fan-forced). Grease and line deep 26cm x 36cm baking dish. Make cake according to directions on packets, pour into baking dish; bake about 1 hour. Stand cake in pan 5 minutes; turn onto wire rack to cool.
2.Place cake on prepared board, top-side up. Using melon baller or small teaspoon, scoop about five deep holes into cake, reserve scoops of cake. Fill holes with half the M&M’s; top with reserved cake.
3.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.
4.Tint half the butter cream with blue colouring; tint one-third of the remaining butter cream with yellow colouring. Tint two-thirds of the remaining butter cream green. Reserve remaining plain butter cream.
5.Cover top of island with green butter cream. Spread yellow onto a few edges of island to resemble the beach; sprinkle yellow butter cream with brown sugar to resemble sand. Swirl blue butter cream with plain butter cream; spread over remaining cake to resemble water.
6.Break tip off waffle cone, push cone into cake for volcano; fill volcano with remaining M&M’s through peak. Using red decorating gel, pipe around top of cone to make lava.
7.Position chocolate-covered fruit and nuts to form paths. Position animals and trees on island. Using black decorating gel, mark a black cross for the treasure.
You will need to buy a 300g packet of chocolate-covered fruit and nuts for this cake.Note