1. Cream the butter and sugar together until pale and fluffy.
2. Slowly add the beaten eggs whilst still beating the mixture.
3. Add the lemon zest.
4. Sieve the flour and baking powder and add to the mixture.
5. Add the lemon juice. Combine well. Divide the cake batter into 4 equal parts. Colour 2 with red and 2 with yellow.
6. Marble the cake mixture into sprayed, lined hemisphere tins. Place the tins on top of a cooks ring place on a baking tray and bake at 150°C until golden brown, or until a toothpick comes out clean, about 80 minutes. Cover with foil if the cakes begin to brown too much.
7. Leave the cake to cool in the cake tin for 5 minutes and then turn the cake out onto a cooling rack.
8. Carve a small crater in the middle of each cake and fill with candy rocks, glitter, crushed oreos.
9. Spread buttercream frosting on the cake board and place one cake on top. Spread more icing along the edges of the cakes and stick the two together to create the globe.
10. Apply buttercream crumb coat in sea blue. Chill.
11. Cover the cake in sea blue frosting with a semi-smooth finish. Pipe on leaf green for the land and use a small palette knife to create details. Pipe white icing to create ripples and waves in the ocean. Create the poles with white icing. Add silver leaf to whites for some shimmer.
12. Cut the cake to find the surprise inside.