Pat the roast dry with paper towels. Trim the fat cap down to ¼" on top if needed, and cut a crosshatch pattern in the fat cap. Remove the rib bones (if desired) using a sharp boning knife.
Season: Lightly coat with oil and then generously season all sides with kosher salt (about 1 teaspoon per pound), and pepper. Refrigerate for 24-48 hours
Use butcher twine to tie the rib roast so it is a nice round shape and cooks evenly. If desired, you can tie the rib bones back in place as well. I prefer to leave them off and smoke them separately or use them to make beef stock.
Place the rib roast on a cooling rack on a baking sheet pan, then into the refrigerator uncovered for 24 to 48 hours (or even 3 days if you have time).
Smoke the Prime Rib
Temper the meat: Remove the roast from the refrigerator to sit on the counter to temper for 2 to 3 hours prior to cooking.
Set up your smoker for indirect cooking at 250° F (121° C) with a water pan in place according to the manufacturer's instructions. Use 2 to 3 oak wood chunks for charcoal smokers or pellets for a pellet smoker.
Insert a leave in remote probe thermometer into the center of the roast and set the alarm to go off at 118° F for the pull temp for a medium-rare finish.
Place the rib roast in the smoker and cook for approximately 25 to 30 minutes per pound (3 to 3 ½ hours) until the internal temperature reaches 118° F (47° C) for medium-rare.
Remove the roast from the smoker and rest uncovered for 30 minutes.
Sear
Preheat grill, a heavy-bottom skillet or broiler on high (500° or 550° F).
Sear for 1 to 2 minutes per side until dark and crusty, about 4 to 8 minutes total. (remove the tied on rib bones before searing). The finished temperature should be 130-134° F (54-56° C) for medium-rare
Transfer to a large cutting board and rest it for 5 minutes before slicing against the grain into ½" to ¾" pieces.
Sprinkle with finishing salt and enjoy!
Notes
Cook to temp not time.
Slice only what will immediately be served
Salt amount: 1 teaspoon per pound of beef (Diamond kosher). See the conversion chart for other types of salt.