Preheat oven to 190 degrees C with the rack in the middle position. Grease baking trays or line with baking paper. Sift together the flour, bicarb soda and salt.
Break the chocolate into chunks, place in a microwave-safe bowl and microwave on High until the chocolate melts; about 90 seconds. Stir the chocolate until smooth and set aside to cool.
In a large bowl cream 125g butter, brown sugar and white sugar until light and fluffy; pour in the egg and beat until smooth. Mix in the red food colouring and chocolate scraping the bowl down regularly until evenly blended; about 30 seconds. Add half of the sifted dry ingredients stirring until well incorporated.
Beat in the sour cream and mix in the remaining dry ingredients. Fold in the chocolate chips. Drop spoonfuls of the dough 5cm apart onto prepared baking trays.
Bake one tray at a time in the preheated oven until they spring back when pressed; about 9 minutes. Cool on the trays for 5 minutes before removing to cool completely on a wire rack.
For the cream cheese icing; cream 65g butter, cream cheese and vanilla until smooth. Blend in the icing sugar in half cup portions until the icing reaches the desired consistency.