Ham and Cheese Slider Melts

Ham and Cheese Slider Melts - It is so simple but so yummy. I know these are going to be my go-to party food.

Ingredients:

10 tablespoons of unsalted butter, divided into 6 tablespoons and 4 tablespoons: I made two batches, using most inside and another smaller version as topping.
1 small onion, minced
3 tablespoons Dijon Mustard, and 1 separate tablespoon of mustard
3 teaspoons Worcestershire Sauce, and 1 separate teaspoon of Worcestershire
3 teaspoons of poppy seeds, and 1 separate teaspoon of poppy seeds
1 package of 12 Hawaiian sweet rolls
1 pound of shaved deli ham- I used Black Forest. You need at least a minimum of 12 slices
1 cup shredded cheese + 6 slices of cheese of your choice- popular options might be Swiss or Havarti or Provolone or Monterey Jack, or indulge with Gruyere. I used shredded Monterey Jack and slices of Swiss