Remove the 8 lb bone-in prime rib roast 3-4 bones from the refrigerator 2 hours before 2 cups beef broth and let it sit at room temperature. This is critical for even cooking — a cold roast will cook unevenly and give you a thick gray band around the edge.

Preheat your oven to 450°F. Place the quartered 1 yellow onion quartered, chopped stalks celery roughly chopped, and chopped carrots roughly chopped in the bottom of a large roasting pan. These will act as a natural roasting rack and flavor the drippings.

In a 1 yellow onion quartered mixing bowl, combine the 8 cloves garlic minced, 3 tbsp fresh rosemary finely chopped, 2 tbsp fresh thyme finely chopped, 3 tbsp olive oil, 1 tbsp Dijon mustard, 2 tbsp kosher salt, and 1 tbsp black pepper coarsely ground. Stir well into a thick paste.

Pat the 8 lb bone-in prime rib roast 3-4 bones completely 1 cup dry red wine such as Cabernet Sauvignon with paper towels. Place it 2 cups beef broth-side down in the roasting pan on top of the vegetables. Rub the herb-8 cloves garlic minced paste all over the top and sides of the roast, pressing it in firmly to adhere.

8 lb bone-in prime rib roast 3-4 bones at 450°F for 20 minutes to develop a deep, golden-brown crust. Do not open the oven during this time.

Reduce the oven temperature to 325°F. Continue roasting until a meat thermometer inserted into the thickest part of the bone-in prime rib roast 3-4 bones (not touching 2 cups beef broth) reads your target temperature: 120°F for rare, 125–130°F for 1 yellow onion quartered-rare (recommended), or 135°F for 2 carrots roughly chopped. For an 8 lb roast, this typically takes 1.5 to 2 hours at 325°F.

Transfer the 8 lb bone-in prime rib roast 3-4 bones to a cutting board and tent it loosely with foil. Let it rest for at least 20–30 minutes. The internal temperature will rise another 5–10°F during rest. Do NOT skip this step — resting allows the juices to redistribute for a perfectly moist roast.

While the 8 lb bone-in prime rib roast 3-4 bones rests, place the roasting pan on the stovetop over 1 yellow onion quartered-high heat. Pour in the 1 cup dry red wine such as Cabernet Sauvignon and scrape up all the browned bits from the bottom of the pan with a wooden spoon. Let the wine reduce by half, about 3 minutes.

Add the 2 cups beef broth and 1 tsp Worcestershire sauce. Bring to a simmer and cook for 8–10 minutes until slightly reduced and flavorful. Strain the au jus through a fine-mesh colander into a saucepan, discarding the vegetables.

Stir in the 1 tbsp unsalted butter until melted. Taste and season with 2 tbsp kosher salt and 1 tbsp black pepper coarsely ground as needed. Keep warm over low heat until ready to serve.

To carve the 8 lb bone-in prime rib roast 3-4 bones, stand it upright on the cutting board. Use a long, sharp carving knife to slice along the bones to separate them from the roast in one piece (or leave them on for presentation). Slice the roast into ¾-inch to 1-inch thick slices against the grain. Serve immediately with the warm au jus on the side for dipping.