Blend all ingredients in a food processor or blender. Remove any straggling layers of fat from the rack of lamb (it’s best to have your butcher do this if you are new to the concept). Don’t remove it all, but you will need that meaty surface for the seasoning paste to stick.
Slather garlic-herb paste onto the surface of the meat, and let stand for 10 minutes or so.
Set your pellet cooker temperature for 400 degrees F.
Once ready, place your rack of lamb seasoned side up in the center of the grill. Cook for about 20 to 25 minutes depending on the desired doneness. For medium-rare, remove the rack of lamb when then internal temperature, measured in the center of the meat portion reads 120 degrees F. For medium, cook to 130 degrees. For medium-well, cook to 140 degrees.
Cover the rack of lamb with aluminum foil immediately after removing it from the grill. Let it rest for 5 to 7 minutes.
Carve into individual chops and serve.