Mint Choc-Chip Layer Cake

g/8 oz Doftened unsalted butter

g/ 12 1/2 oz Dark muscovado sugar

Large eggs

Cocoa powder mixed plus 3 tbsp boiling water

g/ 3 oz Dark chocolate - melted

ml/ 1/2 cup + 2 tbsp Buttermilk

g/ 12 1/2 oz Plain (all purpose) flour

Baking powder

Bicarbonate of soda

ml/ 1 cup + 2 tbsp Water - just boiled

g/ 9 oz Softened butter

ml/ 5 tbsp Double (heavy) cream

g/ 17 1/2 oz Icing sugar

Colouring gel - mint green ((optional))

Peppermint extract - to taste ((I used Star Kay and needed 3 1/2 tsp for a fresh minty taste))

g/ 3 oz Dark chocolate - chopped fine