When Sunday dinner is an event, prime rib with Yorkshire pudding is the centerpiece. Rich, impressive, and a high calorie experience you remember.
Preheat the oven to 450°F. Pat the prime rib roast dry, then rub generously with kosher salt, black pepper, Dijon mustard, thyme, and rosemary. Allow the roast to come to room temperature for about 45 minutes.
Place the seasoned roast on a roasting rack in a large roasting pan, fat side up. Roast uncovered at 450°F for 20 minutes to sear, then reduce heat to 325°F.
Continue roasting at 325°F until meat thermometer registers 120°F for rare (roughly 15 minutes per pound; about 2 to 2.5 hours for 6 lbs). Baste occasionally with pan drippings.
While the roast rests after cooking (at least 30 minutes, tented loosely with foil), increase oven to 450°F for Yorkshire pudding. Whisk eggs and milk until frothy, then sift in flour and a pinch of salt, whisking until smooth batter forms. Let rest for 15 minutes.
Pour beef fat into a 12-cup muffin tin (about 2 tsp per cup) and heat in oven until sizzling hot. Pour batter evenly into the cups and bake for 20–25 minutes without opening the oven until puddings are puffed and golden brown. Serve slices of prime rib with Yorkshire pudding hot from the oven.