Step 1: 1) start by putting the dark chocolate chips and butter in a ban marie.
Step 2: 2)sieve the flour and cocoa into a bowl with the sugar in and add the beaten egg and vanilla seeds, and mix.
Step 3: 3)pour in the melted butter and chocolate and mix thougherly.
Step 4: 4)pour mixture into a baking tray and bake for around 15-20 minuites.
Step 5: when the brownie has cooled, melt the milk chocolate chips and butter in a saucepan, then add the sour cream. Pour over the brownie and leave to set, eat!