In a medium-sized sauce pan melt the butter and mix in mustard, Worcestershire sauce, poppy seeds, and onion. Simmer until the onions become translucent about 5 minutes.

Cut the entire package of rolls in half. Do not separate them, keep them intact.

Lightly grease the bottom of a 9″ x 12″ baking pan.

Place the bottom half of the rolls in the prepared pan and spread with half of the onion mixture.

Layer the ham and cheese over the onion mixture. Cover completely from edge to edge.

Replace the tops of the rolls and spread the remaining onion mixture evenly over the surface.

Cover pan loosely with aluminum foil that has been lightly sprayed with non-stick spray. Place in the refrigerator for at least 4 hours or up to 24 hours (the rolls will absorb the butter mustard sauce as they sit).

When you are ready to serve. Remove rolls from the refrigerator and heat oven to 350°F. When the oven in hot, place the covered pan in the oven for 10 minutes.

Remove foil and bake uncovered for another 10 – 15 minutes, or until tops are light golden and slightly crisp.

Transfer rolls onto a cutting board, cut and serve.