I use Mr Bait's method.
In a large jug, mix two eggs with an equal weight of plain flour, using a fork, until you have a dense paste. Then add an equal weight of milk, about 3 tablespoons at a time until the mixture has loosened enough for you to be more generous, and beat well. Once it has loosened to the point where it's not forming thick clumps when more milk is added, you might wish to switch to a whisk. It should have a consistency somewhere between single and double cream.
Leave to stand for 20-30 minutes. It will be slightly thicker.
Place a scant teaspoon of oil in the base of each cavity (just enough to cover the bottom) of a 12-cavity cupcake tin. Turn the oven to 180 of your metric degrees (fan, 200 otherwise) and put the oiled tin inside. By the time the oven is hot and the oil is just smoking, your batter will be ready.
Remove the tin Pour enough batter into each cavity (it should sizzle and bubble, take care) so that they are about 3/4 to just shy of full. Return to the oven until well risen and browned to taste (I prefer mine slightly soft in the base and blonde). the timing for this will depend on your oven, so I suggest you keep an eye on it the first time and just see how long it takes to get the result you like.
Sam