Pineapple-Stuffed Burgers

Directions

1. In a small saucepan, combine the brown sugar, ketchup and mustard. Cook over medium heat for 2-3 minutes, stirring occasionally.
2. Meanwhile, shape beef into four patties. Place pineapple slices on two patties; top with remaining patties. Seal edges; sprinkle with salt and pepper.
3. Using long-handled tongs, moisten a paper towel with cooking oil and lightly coat the grill rack. Grill burgers, covered, over medium-hot heat or broil 4 in. from the heat for 7-9 minutes on each side or until a thermometer reads 160° and juices run clear. Serve on buns with sauce and lettuce.