Cut ham slices in half. Cut cheese into strips. Preheat oven to 325 F. Beat butter, onion, poppy seeds, mustard and Worchestershire together in small bowl. Split rolls. Spread d butter mixture on both cut sides of rolls. Place one piece of ham and 1 slice cheese on bottom half of each roll. Replace tops and place on cookie sheet. Cover r loosely with foil and bake 15 minutes or until cheese begins to melt. These freeze very well. Per appetizer: 135 calories, 8 g total fat (3 g saturated), 264 mg sodium, 20 mg cholesterol, 10 g carbohydrates, 6 g protein.