In a large skillet or grill pan, melt butter. Add onion and cook 2-3 minutes, or until the onions are tender.
Transfer onions to a medium bowl. Add ground turkey, seasoned breadcrumbs, Greek yogurt, egg, garlic, Worcestershire sauce, liquid smoke, and pepper and mix well.
Form meat mixture into 6 patties that are about 1/3 cup each.
Spray skillet or grill pan that you used to cook the onions with cooking spray and set over medium heat. Add turkey patties to the pan and allow to cook 3-4 minutes on both sides.
Meanwhile, in a small bowl, combine the ingredients for the blue cheese pub sauce. Be sure to push down the large crumbles of blue cheese with the back of the spoon to make the sauce easier to spread on the burgers.
Once the turkey burgers are fully cooked, top each with 1 tablespoon of the blue cheese pub sauce. Top each bun with one sauce coated turkey burger.