(adapted from Time-Life, Foods of the World, Cooking of the British Isles)

To make the batter in a blender, combine the eggs, salt, flour and milk in the blender jar, and blend at high speed for 2 or 3 seconds. Turn off the machine, scrape down the sides of the jar, and blend again for 40 seconds. (To make the batter by hand, beat the eggs and salt with a whisk or a rotary or electric beater until frothy. Slowly add about a quarter of the flour , beating constantly. Then pour in a quarter of the milk in a thin stream and blend; repeat adding first some flour, then some milk, until all is incorporated and mixture is quite smooth and creamy.  A few lumps are okay, since this batter will rest for an hour in the refrigerator.)  
Refrigerate for at least 1 hour.
Preheat the oven to 400° F.
In a 10-by-15-by-2 1/2-inch roasting pan, heat the fat over moderate heat until it splutters. Briefly beat the batter again and pour it into the pan. Bake in the middle of the oven for 15 minutes, reduce the heat to 375° F, and bake for 15 minutes longer, or until the pudding has risen over the top of the pan and is crisp and brown.
With a sharp knife, divide the pudding into portions, and serve immediately.

Yorkshire pudding is always served with roast beef.

Great when roast is left in oven to drip on Yorkshire. Peter has mastered this; observe his technique sometime when we are not using SWK's approach to roast beast..

Preheat oven to 350° F. (moderate oven).

Grease a baking dish, 12 x 7 x 2 ½-inch size.

Prepare batter:

In medium-size bowl, sift together
1 1/2 cups* sifted all-purpose flour
1 1/2 teaspoons baking powder
1 teaspoon salt
In second bowl, beat until very light
4 eggs

Stir in

1 ½ cups milk
3 teaspoons melted butter (optional)

Slowly blend egg mixture into dry ingredients. When blended, beat with rotary beater just until batter is smooth.

(Note: this is a much lower temperature than is typical for either popovers or Yorkshire Pudding. It makes this an easy dish to cook alongside some other complementary dish.  Of course, if you have room in your oven; if you have two ovens, the whole issue of temperatures and cooking times may be irrelevant.)