Preheat George Foreman grill by plugging it in, or setting it to MAX, 400°F or setting 4.
In a small saucepan, melt butter over medium heat. Add cherries, apple cider vinegar, lemon juice, brown sugar and onions. Stir occasionally until bubbling.
Continue to cook until onions are soft, about 5-6 minutes.
Meanwhile, in a large bowl, add harissa and ground beef and stir to combine. Season with onion and garlic powder, salt and pepper.
Form into 6 patties, place on preheated grill and close lid.
Grill burgers for 4-6 minutes until it reaches an internal temperature of 135°F-155°F,
Note: If grilling on Indoor/Outdoor grill, grill for 4-6 minutes per side.
Top each burger with slice of cheese and continue to grill until melted, about 1-2 minutes. (Note: Harissa will make burger look red inside even though it’s cooked. Make sure to take temperature to confirm burger is cooked to desired doneness.)
Place burger on bun and top each with cherry sauce and top bun. Serve immediately.