Cheesy Stuffed Turkey Burgers

1 Tbsp. olive oil
1/2 C. sweet onion, finely minced
1 Tbsp. fresh rosemary, finely minced
1 lb. ground turkey
1/2 tsp. coarse salt
1/4 tsp. freshly ground black pepper
1/2 C. of your favorite shredded cheese
4 whole wheat burger buns

Heat oil in a small skillet over low heat. Add onion and rosemary and saute until tender (8-10 min.). Let onion cool a bit, then place in mixing bowl with turkey, salt and pepper. Combine ingredients well and divide into into eight uniform patties. Place 2 Tbsp. of cheese in the center of 4 of the patties, then place the remaining 4 patties over the cheese, sealing the edges.
Preheat grill to high and cook burgers 4-5 min. on each side or until no pink remains and they are browned and firm.
Serve with your favorite fixings.