Cream together the margarine and sugar in a mixing bowl until it is soft and fluffy.
Break the eggs one at a time into a cup checking there is no shell, then beat them in one at a time.
Stir in the flour and cocoa powder, then add the baking powder and milk.
Mix to a smooth, soft batter then pour into a 24cm cake tin.
Bake in the oven at 180 C / Gas 4 for 30 minutes, checking every 5 minutes once you get to 20 minutes. Place it on the side to cool.
Whilst the cake cools, prepare the Nutella icing. Then in a seperate bowl mix a tablespoon of icing sugar with a tablespoon of water, then mix in some extra icing sugar a little at a time until you have a white icing of a thick consistency.
Remove the cake from the tin and cover the top with Nutella icing.
Drizzle a teaspoon of the thick white icing over the cake. Leave to set for 5 minutes before continuing.
Write the person's name or happy birthday or something else on top of the cake with the designer icing, you could use other designer icing but I've found that Dr Oetker is the best as the easy squeeze bag makes it really easy to pipe.
Dust a little icing sugar over the cake, leave to set and enjoy!
Silicone cake moulds work really well with this recipe as they peel off the cake really easily.
I got the basic chocolate cake recipe for this from "Cookbook for girls" by Denise smart, I highly recommend it for any young girls who love to bake as the recipies are simple but effective.
You could make this a 2 tier cake by dividing the mixture into two 20cm cake tins and using a bit more Nutella icing for the middle.