1/2 lb. butter
3 tbsp. regular mustard
1 sm. onion, grated
1 tbsp. Worcestershire sauce
1 1/2 tbsp. poppy seeds
1 lb. shaved ham
1/2 lb. Swiss cheese, shaved
16 hamburger buns

Soften butter and mix well with mustard, onion, Worcestershire sauce and poppy seeds. Spread on both sides of buns. Fill generously with ham and Swiss cheese. Wrap in foil and place in freezer or in oven at 275 degrees for 20 minutes. For those taken from freezer, defrost somewhat before heating or increase the heating time.