Yorkshire pudding batter: one, one, one.
ONE egg, ONE cup of flour (self raising or plain, depending on who you listen to), ONE cup of milk. A bit of salt and pepper won't go amiss here.
Mix. An electric beater helps, if you have one. Let the mix stand - if you feel like it - whilst you cook the rest of the dinner.
Now, the important part. Oven on maximum with your cooking dish in there.
When all is hot, add fat/oil (dripping is best - and only a bit - just enough to coat the cooking dish). Let the oil get really hot, perhaps it will even start to smoke! Now QUICKLY add the batter.
So there you have it. A simple batter cooked in a really, really hot pan Get as fancy as you like, but at heart it's just batter in a bit of fat.