Combine 1/2 cup cheese, onion and jalapeno in a small bowl.
Divide the ground chuck into 16 equal portions, each about 5-inches in diameter. Divide the cheese mixture evenly among 8 patties. Top each with a second patty and squeeze the edges together, sealing the cheese mixture inside. Seasoning evenly with the Durkee Perfect Burger Seasoning.
Grill 8 to 10 minutes, turning once or twice. During the last minute of grill time, toast the buns, cut sides down. Remove the burgers and buns from the grill and top the burgers with equal amounts of the remaining cheese. Serve the burgers on buns with lettuce, tomatoes and your favorite condiments.