Melt the butter in a pan and add the golden syrup. Then whisk in the eggs and the milk
Sift the flour, bicarbonate of soda and cocoa powder into a bowl, and add the caster sugar. Then mix in the wet ingredients and pour into a lined tray
Bake on 175C/350F/Gas Mark 4 for 20 minutes
Once the cake is fully cool, melt the white chocolate and drizzle it over the cake