Ham and Cheese Roll

12 hard rolls
12 slices swiss cheese
1/2 lb shaved ham
1 cube butter
1/2 c mustard
2 Tbsp chopped onions
2 tsp caroway seeds
Mix all these together very well
Cut hard rolls in half. Spread both sides of roll with mixture. Put 1 slice swiss cheese and shaved ham. Wrap in foil and set on a cookie sheet. Put in the oven at 350 degrees for 20 min.