Preparation

• 1
  Preheat the oven to 180 degrees, 160 degrees fan oven. Line a 21cm square baking tin with baking parchment for the chocolate sponge.
• 2
  Sift the flour and baking powder into a bowl then stir in the sugar.
• 3
  Cut the butter into small pieces, place in a saucepan with the cocoa powder then pour in the boiling water. Stir over a low heat until the butter melts and the cocoa is well combined, then simmer gently for less than a minute.
• 4
  Gradually add the flour mixture to the pan, stirring it in well.
• 5
  Beat the egg in a small bowl and then whisk in the milk. Add to the cake mixture, stirring well together.
• 6
  Spoon the cake mixture into the prepared tin, shake gently to level the mixture then bake for 20 minutes. Use the skewer test to make sure that it is done. Leave to cool.
• 7
  Now make the topping. Sift the icing sugar and the cocoa powder into a food processor or mixer. Add the butter, cut into small pieces. Mix together well
• 8
  the icing sugar may fly about as you do this, so be careful!
• 9
  Add the milk a little at a time, pulsing to mix it into the mixture.
• 10
  Break the milk chocolate into pieces and melt gently in a small pyrex bowl over a pan of simmering water. Pour it into the topping mix and beat for several minutes until it is light and well mixed.
• 11
  Use the baking parchment to lift the cooled cake out of the tin. Thickly spread the topping evenly onto the cake.
• 12
  Chop the mini eggs into halves or pieces
• 13
  this is not easy! You may prefer to leave them whole. Arrange them onto the cake, pressing them into the topping. Chill the cake in the fridge to firm up the icing before slicing it into squares or slices.