Preheat oven to 350
Assemble sandwiches with a slice of ham and a half slice of cheese on the bottom half of each roll and top with the top half. Place the assembled sandwiches close together on the baking sheet or in the pan.
Combine the butter, sugar, mustard and Worcestershire sauce. Microwave until the butter is just melted, about 30-40 seconds. Add the poppy seeds and stir until combined.
Drizzle the butter mixture evenly over the sandwiches.
Bake in the oven until the cheese has melted and the butter mixture starts to carmelize, about 10 minutes. Serve warm.