Step 1

Preheat the oven to 160C. Grease and line a 24cm round springform cake pan.

Step 2

Sift the flour, cocoa powder, baking powder and bicarbonate of soda into a bowl. Set aside.

Step 3

Melt the dark chocolate in a heatproof bowl set over a pan of barely simmering water (don't let bowl touch water). Cool slightly.

Step 4

Beat butter and sugar with an electric mixer until light and fluffy. With beaters on medium speed, add vanilla, then add eggs, 1 at a time, beating well after each addition. Pour in cooled chocolate and beat until well combined. Beat in a third of sifted ingredients, followed by a third of the milk. Repeat until all ingredients are incorporated, beating until smooth.

Step 5

Pour mixture into the pan and bake for 45-55 minutes until risen and a skewer inserted in the centre comes out clean. Cool in the pan on a rack for 10 minutes, then invert onto rack to cool completely.

Step 6

To serve, spread the icing over the top and sides of the cake using a hot palette knife, then decorate with chocolate curls.

Step 7

To make chocolate ganache: Melt 150g chopped dark chocolate with 125ml pure cream and 20g unsalted butter in a heatproof bowl set over a pan of simmering water (don't let the bowl touch the water). Stir until well combined, then set aside for 30 minutes to cool and thicken before use.

Step 8

To make chocolate curls: Using a palette knife, spread melted chocolate 2-3mm thick on a hard clean surface such as a glass chopping board or marble slab that you can move. Stand at room temperature until almost set. Shave curls using a peeler or palette knife, pulling towards you at an angle. If the chocolate breaks, it is set too hard - leave in a warm place until more pliable. To make small curls, simply run a peeler along the side of a block of dark chocolate.