Allow the roast to stand at room temperature for 30 to 40 minutes before grilling.
Prepare the grill for indirect cooking over medium heat (180° to 190°C).
In a food processor mince the garlic, rosemary, basil, salt, and pepper. Add the mustard and oil and process to form a paste. Smear the paste all over the top and sides of the roast.
Brush the cooking grates clean. Grill the roast, bone side down, over indirect medium heat, with the lid closed, until the internal temperature reaches 48º to 51ºC for medium rare, 1½ to 2 hours. Transfer the roast to a cutting board and remove the bones. Loosely cover the roast with foil and let rest for 20 to 30 minutes (the internal temperature of the roast will rise a few degrees during this time).
Brush the cooking grates clean. Grill the roast, bone side down, over medium heat, with the lid closed, until the internal temperature reaches 48º to 51ºC for medium rare, 1½ to 2 hours. Transfer the roast to a cutting board and remove the bones. Loosely cover the roast with foil and let rest for 20 to 30 minutes (the internal temperature of the roast will rise a few degrees during this time).
While the roast rests, make the dressing. Place the cream and garlic in a medium saucepan. Bring the cream to a boil over medium-high heat on the stove, and then lower the heat to a simmer. Cook until the cream coats the back of a spoon, 5 to 10 minutes. Remove the pan from the heat. Add the cheese, stirring to help it blend into the cream. Season with pepper.
Related Grill Skills
Slicing Garlic
Carve the roast into 12-millimeter-thick slices. Serve warm with the dressing.
