I've recently bought one of these
If you look on Amazon you will find literally dozens of books of recipes for cupcakes, which is quite amazing really, since, give or take a few additions, the basic idea is sponge cake baked in individual cases and decorated however you like. So call them Cupcakes if you're modern, or Fairy Cakes if you're posh, or, if you're from Yorkshire, more prosaically Buns, it all comes down to a fairly basic recipe and the rest is up to your imagination and patience. I fall back on my usual all in one sponge cake recipe, which I rehearse below -
All in one Sponge
1 pack 8oz/250g of butter at room temperature
8 ounces/250g of self raising flour
1 rounded teaspoon baking powder
1 tablespoon of cornflour
8 ounces/250g of caster sugar
1 teaspoon vanilla essence
about 2 tablespoons milk
Put everything in food processor and switch on till blended. That's it. You might want to mix it without the milk first and then add as much milk as you think you need to get a soft, smooth, but not too runny mixture. Depends on the size of your eggs really.
Spoon into little cake cases or larger muffin cases or mini muffin cases, about 2/3rds full, and bake until golden.And when cold decorate with fondant, butter icing, glace icing, or whatever you like.