These Italian beef sliders are made with sweet Hawaiian rolls, deli roast beef, provolone cheese, pepperoncini, and a seasoned buttery topping.
Preheat the oven to 350 degrees F. Butter or lightly grease the bottom of a 13-by-9-inch baking dish.
Without separating into individual rolls, slice the top half of the bread off the bottom. (Make sure the bottom portion is thicker than the top!) Place the bottom portion of the rolls in the prepared baking dish.
Layer half of the cheese on top of the bottom rolls. Next layer all the roast beef on top. Add the pepperoncini on top. (We've made these with 1/2 cup all the way up to 1 cup of pepperoncini. I prefer more, but my boys like less; add to your personal preference!) Finally, layer the last half of the cheese on top. Place the top section of rolls on top of everything.
In a small bowl, combine the completely melted and slightly cooled butter, dijon mustard, poppyseeds, Italian seasoning, dried minced garlic, dried minced onion, and Worcestershire sauce. Season to taste if desired -- I add 1/4 teaspoon salt. Whisk to combine. Using a pastry brush, liberally brush the butter mixture over the tops and sides of the rolls until well coated. Some of the butter mixture will pool at the bottom of the pan which is fine -- this will help season the bottom section of rolls!
Bake, covered with foil, for 20 minutes. Remove foil and bake for another 3-5 minutes or until cheese is gooey/melty and tops of rolls are slightly crispy (watch carefully). Remove, cut apart with a very sharp serrated knife, and serve while hot!
*Since these sliders are baked you want to start with the roast beef being as rare as possible. That way it won't get over-cooked in the oven :)