To make the sponge, sift the flour in a large bowl, add the baking powder, sugar, bicarb of soda, salt, and cocoa powder.
Separately, whisk the eggs, add the milk, oil and vanilla extract.
Combine the wet ingredients with the dry ingredients, you will get a thick smooth batter.
Pour the boiling water over the batter, and mix well to get a runny smooth batter.
Line 2 cake tins with non-stick paper (mine are 20 cm, 8 inches), and divide the batter evenly.
Bake in the preheated oven at 180 degrees Celsius (360 Fahrenheit) for 30-35 minutes or until a skewer inserted in the middle comes out clean.
Leave to cool completely.
To make the buttercream, add the sifted icing sugar and soften butter to a food processor, and blitz until smooth.
Add the cocoa powder and mascarpone to get a smooth cream (I used a kitchen aid, but a hand mixer is as good).
When the sponges are cooled down, spread some of the cream on top of one sponge, top with the other sponge, then spread more cream on top and on the sides.
To decorate, slice the mini creme eggs in half and spread them around the top, then add the mini eggs in between them.
Happy Easter!