Preheat oven to 350°F (175°C) and slice slider buns horizontally.
Place the bottom half of the buns in a baking dish.
Layer roast beef evenly over the buns.
Add provolone cheese slices on top of the beef.
Place the top half of the buns over the cheese.
Mix melted butter, garlic powder, onion powder, Worcestershire sauce, and Dijon mustard.
Brush the mixture over the tops of the buns.
Cover with foil and bake for 15 minutes.
Remove foil and bake an additional 5–10 minutes until golden and cheese is melted.
In a saucepan, combine beef broth, Worcestershire sauce, garlic powder, salt, and pepper.
Heat the au jus until warm.
Slice sliders and serve warm with dipping sauce.