1 preheat the oven to 190 degrees. Line a 12 ring muffin tin with paper cases. Put the butter ,caster sugar and dark muscavado sugar into a bowl and beat well. Beat in the eggs , cream and milk until thoroughly mixed. Sift the flour,bicarbonate of soda and cocoa powder into a separate bowl and stir into the mixture. Add the choclate chips and mix well. Spoon the mixture into the paper cases. Bake in the oven for 25 to 30 minutes. Turn out on to a wire rack and leave to cool completly. Store in an airtight container until required.