Hot Foil Sandwiches

1lb chipped chopped ham 

1 medium onion (chopped) 

1 stick butter (softened not melted)

2 full Tablespoons poppy seeds

4 level Tablespoons of prepared yellow mustard 

1  bag shredded swiss cheese 

hamburger buns or mini sliders - your choice

Mix all ingredients together.   Fill buns with mixture.  Wrap sandwiches in foil and cook for 20 min at 350 degrees.   If frozen bake 45 min but keep an eye on it after 30 min - oven temps may differ.