Remaining chipotle pepper puree may be frozen in a zip-top plastic freezer bag to use at another time.
Shape patties like a pro: Cut the unwrapped ground meat into the number of patties called for in the recipe; then gently roll portions into balls, and flatten by pressing each one once with the palm of your hand.
Process chipotle peppers in a blender until smooth. Combine ground beef, steak seasoning, and 3 to 4 tsp. chipotle pepper puree, in a large bowl until blended. (Do not overwork meat mixture.) Reserve remaining puree for another use.
Shape beef mixture into 12 (4-inch) patties; place 1 cheese slice on each of 6 patties. Top with remaining 6 patties, pressing edges to seal. Cover and chill 30 minutes to 8 hours.
Preheat grill to 350° to 400° (medium-high) heat. Grill patties, covered with grill lid, 6 to 7 minutes on each side or until beef is no longer pink in center. Serve burgers on buns with desired toppings.
Note: We tested with McCormick Grill Mates Montreal Steak Seasoning.