Cream together the butter and sugar until light and fluffy.

Gradually add the eggs one by one, mixing in between.

Sift in the flour and baking powder and fold in.

In a separate small bowl mix together the cocoa powder and boiling water to a paste then add to the mixture, stirring to combine.

Once fully combined, carefully pour into the 3 prepared tins in equal measures.

Bake the sponges in the oven for 25-30 minutes or until a skewer comes out clean when inserted in the centre of the cake.

Once baked, leave the sponges to cool on a wire rack.

Once fully cooled, carefully cut out a large circle from the centre of two of the sponges using a pastry cutter, these will become the bottom and middle sponges.

Place the bottom base on a cake board or cake stand that you want to present your cake on (it will be difficult to move once filled).

Beat together the icing sugar, cocoa powder and butter to make your buttercream (you may need to add a splash of milk to loosen up).

Spread a thin layer of buttercream on the bottom layer of your cake (not covering the hole) and place the second layer on top.

Fill the hole in the centre with your chocolate sweets.

Spread a thin layer of buttercream on the top of the sponge and place the remaining sponge layer without the hole on top to seal in the sweets.

With the remaining buttercream spread generously on the outside of the cake (or pipe if preferred).

Decorate with chocolate sprinkles and serve.