While the meat is resting, make Yorkshire pudding. Turn the oven up to 450° F.
Whisk together the flour, salt and black pepper in a bowl.
Put about 1½ teaspoons of drippings, oil or clarified butter into each hole in a nonstick Yorkshire pudding tin or in a large nonstick muffin tin. Put the tin in the oven to get the fat very hot.
Whisk the eggs a bit to break them up, then stir them into the flour mixture.
Still whisking, slowly add the milk until you have a smooth batter.
Transfer this batter to a liquid measuring cup with a spout.
Open the oven door. The fat in the muffin tin should be almost smoking. Quickly pour the batter into each hole, filling no more than ¾ of the way. The fat should sizzle when you pour the batter. Work quickly, so you don't lose all the oven heat.
Bake, without opening the oven door, for 15-20 minutes, until the puddings are a deep golden brown and very well risen and crisp.
Serve hot alongside the roast.