Cake
60g unsalted butter, room temp
150g caster sugar
1 egg, lightly beaten
10g cocoa powder
20ml red food colouring, gel/paste
½ t vanilla
120ml buttermilk
150g plain flour
½ t salt
½ t bicarb soda
1 ½ t white wine vinegar

Frosting
300g icing sugar, sifted
50g unsalted butter, room temp
125g cream cheese, slightly softened

Preheat oven 170.  LIne 12-hole cupcake tin.  Beat butter and sugar with electric mixer until light and fluffy.  Slowly add egg until all well mixed.  Separately mix red colour, cocoa, vanilla until becomes thick paste, then add to butter mixture - batter should be deep red/rose. Beating on slow speed, slowly add half buttermilk then half flour, repeat.  Add salt, bicarb, vinegar and beat on high speed for 2 minutes after combined.
Fill cases 2/3 full, bake 20-25 mins.  Cool slightly in tray then move to cooling rack.
Beat icing sugar and butter until well mixed, then add small cubes of cream cheese and beat until light and fluffy, approx 5 mins.  Pipe or scoop frosting on top when cakes are cold.