01 -
Lightly grease a 9x12 inch baking pan with butter.
02 -
Using a serrated knife, slice the entire block of Hawaiian rolls in half horizontally without separating them. Set top half aside.
03 -
Place the bottom half of the rolls into the prepared baking pan. Lay one ham slice and half a slice of Havarti cheese onto each roll.
04 -
In a microwave-safe bowl, melt butter in 30-second intervals until fully liquid. Stir in Dijon mustard, Worcestershire sauce, onion powder, and poppy seeds until well combined.
05 -
Place the top half of the rolls over the ham and cheese. Brush the butter mixture evenly over the tops of the rolls.
06 -
Cover the pan loosely with aluminum foil and bake at 350°F for 15 minutes. Remove foil and bake an additional 5 minutes until cheese is melted and tops are golden brown.