1. Preheat the oven to 350 degrees F.
2. Cut the slab of buns in half horizontally, so you have the tops and the bottoms in two pieces.
3. Lightly grease a 9 x 13 baking dish and place the bottom buns into the pan.
4. Spread 1/2 the cheese on the bottom buns, then layer on all the turkey to cover the cheese.
5. Spread the cranberries over the turkey so that they are evenly distributed.
6. Cover with the remaining cheese slices and top with the other half of the buns.
7. In a small bowl, melt the butter in the microwave and stir in the poppy seeds, sesame seeds, Dijon mustard, onion powder, Worcestershire sauce, and brown sugar.
8. Using a pastry brush, brush the tops and sides of the buns with the butter mixture.
9. Cover the dish with foil and bake for 15-20 minutes until heated through and the cheese is melted.
10. Remove the foil and bake for an additional 5-7 minutes to crisp up the tops of the buns.
11. Allow to cool slightly before serving.