In a small saucepan, melt butter. Stir in Worcestershire sauce and garlic powder, allow to cool for 5-10 minutes.
Pour the butter mixture over the top of the sandwiches. Sprinkle poppy seeds over the top.
Place foil lightly over the top and refrigerate overnight or for 6-8 hours.
Bake at 350 for 15-20 minutes.