Ingredients

• 1 , 4.5 pound
• coarse sea salt , or as needed
• freshly ground black pepper , or as needed
• 1 onion , quartered
• 0.25 cups unsalted butter
• 0.25 cups all-purpose flour
• 0.25 cups red wine
• 1 , 32 ounce
• 4 sprigs fresh thyme

Instructions

1. 1 Preheat oven to 275 degrees F (135 degrees C).
2. 2 Rub beef roast with sea salt and black pepper. Heat a large cast-iron skillet over medium-high heat; sear roast on all sides in the hot skillet, 2 to 3 minutes per side. Turn roast so the ribs and fat side are facing up.
3. 3 Roast prime rib in the preheated oven for 45 minutes; scatter onion quarters around roast and continue cooking until an instant-read meat thermometer inserted into the thickest part of the meat reads 130 degrees F (54 degrees C) for rare, about 2 more hours.
4. 4 Remove roast from skillet, wrap meat in aluminum foil, and let rest for 15 to 20 minutes to let juices reabsorb into the meat. Leave onion pieces in skillet.
5. 5 Pour drippings from skillet into a bowl and skim off excess grease. Return degreased drippings to skillet with onion pieces, place over medium heat, and melt butter in the drippings. Whisk flour into mixture to make a paste, 1 to 2 minutes. Stir red wine into flour paste until smooth. Mix beef stock into pan gravy until smooth; stir thyme sprigs into gravy.
6. 6 Reduce heat to low and simmer gravy until thickened, 5 to 8 minutes. Strain gravy, discard onion pieces and thyme, and serve with prime rib.

Nutrition per serving