Prepare two 9 by 13 pans. Place the bottoms of 12 rolls in each pan.
Place ham on rolls (about 2 slices of shaved ham on each roll).
Cut cheese in four parts and place two parts on each sandwich.
Put the top of the dinner roll on each sandwich.
Melt the butter add the mustard, Worcestershire sauce and dried onion, mix well. Pour half the mixture on each pan of sandwiches sprinkle with poppy seeds, cover and refrigerate overnight.
Bake uncovered in a 350 degree oven for 15 to 20 minutes. Serve hot or at room temperature.
Tips: Turkey can be used instead of ham.
Sandwiches will taste good if baked right away instead of refrigerating overnight.