Prep. time: 15 minutes
Cooking time: 30 minutes

Potatoes

1. Preheat the oven to 240 °C / 475 °F.
2. Place the potatoes in an oiled dish; cook for 30 minutes in the lower part of the oven.
3. Prepare the thyme butter: grind the thyme leaves to a powder and add the butter in pieces.
4. Sprinkle half of the butter over the hot potatoes and keep the rest cold.

Prime rib

1. Season the meat with salt and pepper on both sides, brush with oil and place on a rack set over a broiler pan to collect the cooking juices.
2. Cook in the oven on the middle rack above the potatoes for 10 minutes.
3. Turn the prime rib and cook 20 minutes longer.
4. Let the meat rest out of the oven for 10 minutes, loosely covered with foil, before carving into thick slices, while you leave the potatoes in the turned off oven with the door partially open.

Finishing and serving

1. Meanwhile, sweat the chopped shallots for 2 minutes in a little thyme butter without letting them brown.
2. Serve the beef slices napped with the shallot sauce with the potatoes, sprinkled with the remaining thyme butter.