Crack the eggs into a measuring cup. Make a note of the volume measurement.
Empty the eggs into a bowl, and with a clean measuring cup, measure the same volume of flour as you had of egg, then add to the eggs in the bowl. Then do the same for water -- the same volume of water as you had of egg. Season with a few shakes of salt and pepper. Beat the mixture for 5 minutes with an electric mixture, or by hand, if you are energetic.
Now let the mixture stand for an hour at room temperature (you can skip this step if you like: it only makes the mixture easier to pour.)
Start oven heating to 220 C / 425 F / Gas Mark 7 if it isn't already on; otherwise crank up the heat to the temperature indicated.
Generously grease the pans you'll be making the pudding in. You can do it with oil, shortening, lard, melted dripping, or some fat from a roast you might have in the oven.
When the oven is ready, pop the yorkshire tins in the oven for about 10 minutes; you want the fat in the pans to be very hot before you put the batter in.
Remove the yorkshire tins from the oven, and pour the batter (careful of the spluttering fat) into the tins. Return the yorkshire tins to the oven, and don't open the oven for any reason for at least 15 minutes. The yorkshires are done when they are puffy and golden. Individual ones should take about 15 to 20 minutes. Cooking one entire yorkshire pudding as a cake should take about half an hour.
You can make the yorkshire all one yorkshire in a cake pan, which you'll cut up for serving, or in muffin tins or in special yorkshire pudding tins.