1. Combine cheese, rosemary, and pepper. Sprinkle burgers with salt.
2. Preheat grill pan over medium-high heat. Add patties, and cook 5 to 6 minutes per side or until no longer pink, topping with cheese mixture during last 2 minutes of cooking.
3. Serve Burgers in lettuce leaves with tomato slices; sprinkle with additional rosemary, if desired.