1.Preheat oven to moderate, 180ºC. Lightly grease and line base of two 18 x 28cm cake pans.
2.In a large bowl, using an electric mixer, beat butter and sugar together until light and fluffy. Beat in vanilla.
3.Add eggs, one at a time, beating well after each addition. Fold in flour alternately with milk, beginning and ending with flour. Divide mixture between pans, smoothing tops.
4.Bake 40-45 minutes, until cooked when tested. Cool in pan 5 minutes, before turning onto a wire rack to cool completely.
5.Meanwhile make the butter cream in a bowl, beat butter and vanilla together until creamy. Gradually beat in icing sugar with milk. Reserve 1/3 mixture and tint remainder with food colouring.
6.Place cakes side by side. Cut out cakes using template. Position on serving platter or board. Spread butter cream over top and side of cake, spreading inside lid with the reserved buttercream. Use thin strips of liquorice to outline cake as shown. Cut semi-circles from strap and position for clasps. Arrange lollies across the centre of the chest to create the treasure.
To make template, trace our cake and enlarge it to suit your needs.Note