PREHEAT grilll to medium-hot heat. Melt butter in small saucepan on low heat. Add sugar; stir until well blended.
BRUSH butter mixture evenly onto the pineapple, then place on grill. Cook 12 min. or until pineapple is golden brown on both sides, turning frequently.
PLACE 2 pineapple slices on each of 4 dessert plates; top with 1 Tbsp. dressing.