Divide the ground beef into 6 equal parts and form 1-1/2-inch thick patties.
Sprinkle patties with the blackening seasoning and salt. Cook over direct high heat for 8-10 minutes for medium- medium well burgers (155-160 degrees). While the burgers are still on the grill, top with blue cheese crumbles dividing equally between burgers. Close the grill lid to melt blue cheese.
Brush the inside surfaces of the hamburger buns with the melted butter. Place on grill and cook over medium-direct heat for 2-3 minutes. Place burgers on the grilled buns and top with onion, tomato and lettuce. Serve the blue cheese dressing on the side
Yield: 6 burgers