2 sticks butter, softened
3 tsp. poppy seeds
1 tbsp. Worcestershire sauce
3 tbsp. mustard
1/2 c. onion, minced (optional)
2 pkg. party rolls
1/2 lb. sliced ham
1/2 c. Swiss cheese, grated

Combine first 5 ingredients. Slice entire package of rolls lengthwise, while in one piece. Spread mixture on both halves of rolls. Put ham on bottom half and sprinkle with cheese. Place top layer of rolls on ham and cheese. Wrap in foil.

Bake for 15 minutes in a 425°F oven. Cool for a few minutes, then slice and serve.