Preheat the oven to 180°C (170°C fan, gas mark 4) and grease and line two 8″ sandwich tins.
Beat together the softened butter and sugar until light and fluffy.
Add the eggs and continue to mix. Then gradually fold in the flour, cocoa powder and baking powder.
Split the mixture evenly between the two sandwich tins and bake for 20-30 minutes until golden and cooked throughout.
Leave the cakes to cool on a wire cooling rack.
Whilst the cakes are cooling make the buttercream by beating together the butter, icing sugar, cocoa powder and milk until you reach a smooth consistency.
Once the cake is fulled cooled, spread part of the buttercream in the centre and sandwich the two sponges together. Level the top cake and use the remaining buttercream to cover the top and sides of the cake.
Lightly dust the surface with icing sugar and roll the white sugar paste icing into a large circle. Lay over the cake and using your hands or a cake smoother, smooth the top and sides to remove any bumps.
Roll out the yellow and part of the grey sugar paste icing and using small circular cutters and a small knife, cut out the circles for the top of the cake and triangles to make up the bunting effect around the sides. These shapes can be secured to the cake by lightly brushing the underside with a touch of water and gently pushing into place.
To make the elephant topper; roll out a large circle for the body and a smaller circle for the head. Gently ease out part of the icing from the front of the smaller circle to form the trunk.
Pull off two small amounts of grey sugar paste and using your thumb and finger push into two thin circles to create the ears. Repeat this process with the blue sugar paste and stick on top to create the inside of the ears.
Use two small amounts of grey sugar paste icing and roll into two small cylinders to form the feet and slightly larger versions for the arms. These can be attached to the body by lightly brushing with water and pushing into place.
Use a small knife to add detail to the elephant and either an edible black pen to create the eyes or alternatively a small amount of black sugar paste icing.
The balloon was created using a cake pop stick and some of the remaining yellow sugar paste icing. You can also decorate the cake board with any additional sugar paste icing and finish with a satin ribbon.