Preheat your oven to 180°C/160°C fan/Gas 4. Line a muffin tin with 12 paper cases.
Put the spread and caster sugar into a mixing bowl and beat with an electric whisk until pale and fluffy - about 5 minutes. (picture 1)
Add the egg and continue beating until well combined. (picture 2)
Sift in the cocoa powder, add the whole tube of food colouring and vanilla and beat until combined.
Mix in half the yoghurt, followed by half the flour and beat well. Repeat with the remaining yoghurt and flour and beat until fluffy - about 2 minutes. (picture 3)
On a low speed, beat in the bicarbonate of soda and white wine vinegar, then gradually add enough milk so that the mixture drops easily from a spoon. (picture 4)
Divide the mixture between the cake cases, don't worry that they only look half full the mixture will rise when it bakes. Bake for 20 minutes or until a skewer inserted comes out clean. The cakes will be risen and springy to the touch. Once baked, cool in the tin for a few minutes then transfer to a wire cooling rack to cool completely.
Trim the top of the cakes so they are level reserving some crumbs to decorate the icing with later.
To make the frosting, mix the soft cheese, yoghurt, icing sugar and vanilla in a bowl. Swirl on to of the cupcakes with a piping bag and round nozzle if you have them, if not use a spoon to spread a dollop of frosting on top of each cake.
Scatter with cake crumbs to decorate.