Spray a cookie sheet with cooking spray. Place ham and Swiss cheese slices on the bottom of each bread roll and cover with tops; arrange rolls in an even layer on the prepared sheet.

Mix butter, brown sugar, Worcestershire, mustard, and poppy seeds together in a small bowl; spoon over sandwich tops. Let sit for 10 minutes or up to 1 hour.

Preheat the oven to 375 degrees F (190 degrees C).

Bake in the preheated oven, uncovered, until golden on top and cheese is melted, about 12 to 18 minutes.