1/2 lb. butter
3 tbsp. mustard
3 tbsp. poppy seed
1 med. onion, chopped
1 tsp. Worcestershire sauce
3 pkgs. "party rolls"
1 lb. sliced ham
1/2 lb. sliced Swiss cheese

Blend first 5 ingredients. Split rolls lengthwise and spread top and bottom with mixture. Layer ham and cheese. Place rolls back together. Cover with aluminum foil to heat in oven for 10 minutes, or cover with plastic wrap and microwave for 1 1/2 minutes on low. Cut into small servings.