Preheat oven to 180º C.
Cream together butter and castor sugar in a mixing bowl with a hand blender. Add eggs and whisk. Add melted dark chocolate and whisk. Add vanilla essence and whisk well.
Sieve together flour, baking powder, soda bicarbonate and cocoa powder into the bowl and fold in well. Add milk and mix well.
Divide batter equally into two8 inch oven proof baking tins and spread. Place the baking tins in preheated oven and bake for 25-30 minutes.Remove from oven, cool and demould.
To prepare frosting, cream together butter and icing sugar in another bowl with an electric beater. Add chocolate, cocoa powder and milk and whisk well.
Put some frosting on a cake stand, place one cake upside down and spread some frosting on top using a palate knife. Place another inverted cake on top and cover it completely with the remaining frosting.
Dip the palate knife in warm water and level it out. Cover the entire cake with the chocolate pearls.
Cut into wedges and serve.