This is how we have been fixing prime rib for the last couple years and it is delicious.
The morning you are going to eat the prime rib,
1) Combine brown sugar and Montreal steak seasoning in a bowl. There should be enough to cover fat side up of the meat.
2) Rub olive oil on the meat.
3) Rub lots of minced garlic on the fatty side of the meat
4) Put brown sugar mixture over garlic - this should be well covered
5) Scatter red onion slices over the brown sugar mixture
6) Place roast in roasting pan and pour au jus in the pan. Add enough water to come up to half way on the roast.
7) Cover with an aluminum foil blanket and put in the refrigerator.
8) When ready to cook, heat oven to 550.
9) Remove roast from fridge and put into the oven with the foil on. Cook for 15-30 min depending on the size then turn heat to 325.
10) When meat thermometer gets to 145 remove from oven and keep covered for 5-10 minutes. You may have to experiment with pulling out at 140 and letting rest for the medium rare desired.
Prime Rib - bone-in or boneless
Montreal Steak Seasoning
Red onions sliced
Johnny's Au Jus concentrate