Set Traeger to high (450 degrees) with lid up. Once smoking, close the lid and allow to pre-heat. About 15 minutes.
While the grill is pre-heating prepare your meat mixture and prep your toppings.
Add the ground lamb and the rest of the burger ingredients to a large mixing bowl. Mix with your hands, being careful not to over work the meat mixture.
Once well mixed, form mixture into four patties and press your thumb into the center of each. Set aside.
Wash and slice your toppings and prepare whipped feta. Set aside.
Place the burgers on the grill and cook until a crust forms, about 3-4 minutes per side for medium-rare, or about 5 minutes per side for well done. Only flipping once.
Transfer burgers to a plate to rest for 5 minutes before serving.
Place burgers on buns and top with a generous smear of whipped feta.
Layer lettuce, cucumbers, tomatoes and onions. Serve immediately. Enjoy!
Add all ingredients to a food processor and process until smooth. Smother on anything and everything. Enjoy!