Line a 9×13 pan with foil. Preheat oven to 350 degrees.
Cut the rolls in half, lengthwise.
Layer the rolls with mustard (or a jalapeno jelly), turkey, fresh apple slices (leave the skins on), and sharp cheddar cheese.
Place the top layer of buns on top. Cover with foil.
Bake covered for 25 minutes. Remove the foil; rub the top of the sliders with butter, bake an additional 5 minutes, to get the top of the buns toasty!