Become A Traeger Ambassador
Share your Traeger stories on social media and gain exclusive access to gear, content, and experiences.Apply Now
For the marinade, cut the lemon into quarters and remove the seeds. Squeeze the juice into a mixing bowl, reserving the lemon rinds. Add the red wine vinegar, garlic, rosemary, thyme, and salt and pepper and stir until the salt crystals dissolve. Whisk in the olive oil.
Remove any netting from the lamb. Put the lamb into a large resealable plastic bag. Pour in the marinade, and add the onion and the reserved lemon rinds. Massage the bag to distribute the marinade and herbs. Refrigerate for several hours, or overnight.
Remove the lamb from the marinade and pat dry with paper towels. Discard the marinade. When ready to cook, start the Traeger grill on Smoke with the lid open until the fire is established (4 to 5 minutes). Set the temperature to 450F and preheat, lid closed, for 10 to 15 minutes.
Arrange the lamb on the grill grate, fat-side down. Grill 10 to 15 minutes per side for medium-rare (135F on an instant-read meat thermometer), longer if you prefer your lamb more well-done. Let rest for 5 minutes. Slice thinly across the grain, and serve.