Remove roast from the refrigerator while you prepare a charcoal grill for indirect medium-low heat (300-325°F).
In a small bowl, combine garlic, rosemary, salt, pepper and olive oil. Rub all over the roast to coat evenly.
Once the grill is ready, place the roast over indirect heat, rib-side down, and grill with the lid closed for roughly 12-15 minutes per pound. Occasionally open the lid to check the temperature with a meat thermometer and to rotate the roast so that each side is exposed to the hot side of the grill (if you have charcoal on one side versus around the outside of the grill).
When the internal temperature at the thickest part of the roast reaches 125-135°F, remove it from the grill and place in a rimmed dish. Cover with foil and let it rest 20 minutes, until the internal temperature reaches 145°F for medium rare.
Cut away the rib bones, carve the roast with a sharp knife, and serve.
If you’re cooking a larger or smaller roast, adjust the amounts of seasoning and cooking time as necessary.
I use 1 ½ tsp kosher salt for a 4-rib roast, but adjust the salt to suit your taste.
The cooking time is a general guide, but always go by internal temperature! Use a meat thermometer to check the temperature of the thickest part of the roast (avoiding any bone) to determine when the roast is done. You want to aim for about 135°F to remove the roast from the grill for medium rare.
The internal temperature will continue to rise as the roast rests.
Don’t skip the resting step! Resting ensures that the juices are redistributed throughout the roast so that they don’t all leak out onto the cutting board (and all over your kitchen!) during carving.
Use a large cutting board with a groove around the edge to catch any juices when carving.
Heat the oven to 450°F and roast for 20 minutes.
Turn the oven down to 325°F and continue roasting, rotating the pan every once in a while, until the internal temperature reaches 125-135°F.
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