To most Americans, Yorkshire pudding does not seem like a pudding at all: It is savory, not sweet. Think of it as a jumbo popover. As with popovers, the batter must be very cold and the roasting pan very hot: The reaction between the two gives the pudding its puffy form. Make the batter the day before, place it in the refrigerator to chill, and cook it right in the roasting pan while the prime rib rests.
Yorkshire Pudding How-To
2 cups all-purpose flour
1 teaspoon salt
6 large eggs
2 1/2 cups milk
1. Sift together flour and salt. Place in bowl; make a well, and place eggs in center. Slowly whisk eggs into flour mixture until a paste forms. Gradually whisk in 1/2 cup milk. Gradually whisk in remaining 2 cups milk. Cover with plastic; chill in the refrigerator at least 4 hours, or overnight.
2. When roast is finished, set oven at 425 degrees. Deglaze pan, and pour 1/4 cup of the reserved pan drippings into roasting pan. Heat pan and drippings until very hot, about 5 minutes. Remove batter from refrigerator, and shake or whisk well; quickly pour into hot pan. Cook until crisp and golden brown, 20 to 30 minutes. Serve each person a large, warm, crispy-edged wedge of pudding with prime rib.