Recipe(tried): Recipe(tried):How to Roast a 16LB Boneless Prime Rib - HI LISA!

You can cut in half and do both at once or leave whole. For a better presentation, leave whole.

Cover generously with Kosher coarse salt, Cracked black pepper, Fresh Rosemary and a little garlic powder.

320 degrees 18 min per pound. Use a meat thermometer for doneness! This is the only way to tell. The meat will be pink since it's slow roasted and not overdone. Use pan drippings to make au jus.
((Don't believe recipes that say - blast it at 425 for 15 mins the reduce temp ... If you want to pan sear first you can but it'll take a pretty big pan depending on the thickness.))

I make this all the time and it's perfect! It's a direct variation of America's Test Kitchens - and they tried a variety of methods.

ps.Garnish with horseradish, rosemary and dijon mustard if you like.