I had to make a big batch of cupcakes for my husband to take to work last week and it got me thinking about how I have used the same principle recipe for my sponge cakes for years.
I never look at a recipe book unless I'm doing something totally different, because sponge mix is such a simple formula of ingredients to remember.

It's just 2 of everything.

2 eggs, 2oz sugar, 2oz self raising flour, 2oz butter.

Then the bigger the cake/batch of cupcakes you want the more you double up. For example for this batch of 30 cupcakes I used 6 of everything.
When it comes to extras I always like to add a tsp of baking powder for added lift and a tsp of vanilla essence. If I'm making a chocolate cupcake I tend to just add my cocoa powder to taste (always add in around a tablespoon at a time, mix then taste).

I hope this rule will help any new bakers out there, just remember the 2 of everything rule and you can't go wrong, perfect sponge every time. Give it a try!