Heat gas or charcoal grill. In medium bowl, mix beef, 1/2 cup cheese, the garlic-pepper blend and salt. Shape mixture into 4 (4-inch) patties, about 1/2 inch thick.
Place patties on grill over medium heat. Cover grill; cook 11 to 13 minutes, turning once, until thermometer inserted in center of patties reads 160°F. If desired, toast buns, cut sides down, on grill during last 1 to 2 minutes of cooking.
Place patties on bottoms of buns. Top with tomato slices and additional blue cheese. Top with tops of buns.