Preheat the oven to 170°C (150°C Fan, Gas Mark 3). Grease and line a 6cm (2 ¼ inch) deep, 15cm (6inch) diameter round tin. Put the butter in a saucepan with the syrup and brown sugar. Heat gently, stirring until melted. Remove from the heat and cool for 10 minutes.

Reserve 5ml (1 tsp) of the Cocoa Powder. Sift the remaining Cocoa along with the flour and Baking Powder into a bowl. Make a well in the centre.

Mix the egg and milk together and pour into the well, along with the melted syrup mixture and stir until well blended.

Pour into the tin and bake for 50 minutes - 1 hour until risen and just firm to the touch – a skewer inserted into the centre should come out clean. Leave to cool for 10 minutes then remove from the tin and place on a wire rack to cool completely. Wrap in parchment and foil and store for at least 24 hours to allow the flavour and texture to develop.

To decorate, sieve the icing sugar into a bowl along with the reserved Cocoa Powder. Gradually blend in approx. 10ml (2 tsp) warm water to make a smooth, drizzling icing. Transfer to a small uncut piping bag, snip off the end and pipe the icing over the top of the cake allowing the icing to drip down the sides. Stand for a few seconds to firm before serving.