Preheat the oven to 170C and line the tin with the cupcake cases (I use deep muffin cases - these are not fairy cakes)
Using an electric whisk on a medium speed, mix together the butter and sugar until fully combined and pale and fluffy
Add the vanilla extract and the egg whites whilst still mixing. Add the coffee.
Scrape down the sides of the bowl with a spatula and reduce the speed to slow
Pour in a little of the mix at a time and a tbsp of the flour alternately until it has all been added
Have one last stir to make sure the ingredients are all combined and distribute evenly across the cupcake cases (You will need to do 2 batches if you only have 1 muffin tin)
Bake for approx 18 minutes until cooked.
Remove from the oven and leave to cool on a wire rack. Decorate according to your preference (See ideas in post)