Hawaiian Honey Burgers

1/2 cup honey
1/4 teaspoon ground cinnamon
1/4 teaspoon paprika
1/4 teaspoon curry powder
1/8 teaspoon ground ginger
1/8 teaspoon ground nutmeg
2 pounds ground beef
1/4 cup soy sauce
1 can (23 ounces) sliced pineapple, drained
8 hamburger buns, split and toasted
Lettuce leaves, optional

In a bowl, combine the first six ingredients; add beef and mix well. Shape into eight 3/4-in.-thick patties. Grill the burgers, uncovered, over medium-hot heat for 3minutes on each side. Brush with soy sauce. Continue grilling for 4-6 minutes or until juices run clear, basting and turning several times. During the last 4 minutes, grill the pineapple slices until browned, turning once. Serve burgers and pineapple on buns with lettuce if desired.