Use a serrated knife to cut the rolls in half. You can make this extra easy by not separating the rolls—just slice the entire sheet of rolls in half horizontally.
Cut the cheese slices into quarters.
Place the bottom of the rolls into TWO 13x9 inch pans. Top each roll with a slice of ham (folded to fit). Then top that with two pieces of the sliced cheese. Place the tops of the rolls on top of the sandwiches.
Stir together the melted butter, mustard, worcestershire sauce, and onion powder. Pour the mixture evenly over the sandwiches (some butter will pool at the bottom and that is ok!). Sprinkle evenly with the poppy seeds.
Cover the pans with foil and bake for 20 minutes. Uncover and bake for an additional 5 minutes, or until lightly golden brown on top.
Serve immediately.
Notes
Give the butter/Dijon mixture a good stir just before pouring it onto the sliders. Otherwise the Dijon won't be evenly distributed among the sandwiches. Store leftovers in the refrigerator. Reheat in a 350°F oven, covered with foil, for 5–8 minutes or until warmed through. Swap your favorite meat and cheese for the ham and Swiss. Ideas include roast beef and cheddar, turkey and Havarti, ham and Muenster, etc. Use your favorite combo!