Preheat the oven to 180ºc and line a cupcake tin with paper cases.
Beat the eggs whites until they form soft peaks.
Sieve together the flour, cornflour, baking soda, salt and cocoa powder into a bowl and set aside.
Beat the sugar in a bowl until soft and creamy then add in the sugar and beat again. Add in the oil and beat and do not worry if it looks split at this stage as this is normal.
Add the egg yolks one at a time followed by the vanilla and beat until combined and smooth.
Add in the vinegar and at this stage also add in the food colouring until you achieve the colour you want.
Start to add in the dry ingredients. Add this in stages alternating with the buttermilk starting and ending with the dry ingredients.
Do not over mix.
Once combined fold in the egg whites. You will have a thick mixture at this stage.
Scoop into the cupcake cases and place in the oven for around 20 minutes.