Preheat the oven to 160c and grease and line two 20 centimeters sandwich tins.
Beat the butter and sugar together until fluffy.
Add the eggs one at a time. Sift in the flour, baking powder and cocoa, with a drop of milk until you have dropping consistency.
Divide between the tins and bake for for 20-25 minutes.
Leave to cool completely.
Beat the butter and icing sugar together then add the cooled chocolate and continue to beat until light and fluffy. Spread some of the icing on top of one sponge, then put the other on top.
Carefully cut off either side of the cake to make the top of the hedgehog, then cut off the front sections of the middle piece of cake to make the nose.
Cut small triangles off the back of the sides so there isn't a big overhang at the back of the cake.
Add buttercream to the top of the body and the top of both sides, then sandwich the sides together on top of the body. Cover the hedgehog with buttercream.
Once it's covered, use a fork to add a bristly texture to the body. Arrange the buttons in rows like spines and use a Maltesers for the nose and two eyes.
