A juicy rib roast with rosemary-garlic seasoned potatoes cook at the same temperature to help you get this elegant meal on the table faster.
Preheat oven to 400 degrees, with racks in upper and lower thirds. Place beef on a large rimmed baking sheet; season generously with salt and pepper. Roast on upper rack for 45 minutes; move to lower rack.
Remove 3 to 4 tablespoons of fat from beef and place on a second rimmed baking sheet with potatoes, garlic, and rosemary. Season with salt and pepper and toss to combine; place on upper rack.
Roast beef until an instant-read thermometer inserted in the thickest part registers 110 degrees, 45 to 60 minutes more. Remove beef from oven and tent loosely with aluminum foil; let rest until internal temperature registers 130 degrees, about 30 minutes.
Continue to roast potatoes, tossing occasionally, until golden, 25 to 30 minutes more. Slice beef and serve with potatoes.