Why are my cupcakes dry with big air bubble holes in them?

I perfected my cupcake recipe a few months ago but forgot to write it down,I have made a batch today but think I have remembered it incorrectly as they have turned out well risen but dry with holes in them. I thought I'd cooked them for the same length of time and temperature as before but I must have got something wrong,anyone any ideas?and has anybody got a good fool proof cupcake recipe please?