Preheat oven to 350°F (175°C).
Slice rolls horizontally without separating them. Place bottom half in a baking dish.
Layer roast beef evenly over the rolls, then add cheese. Place the top half of the rolls back on.
In a small bowl, mix melted butter, garlic powder, onion powder, and Worcestershire sauce.
Brush butter mixture generously over the tops of the rolls.
Cover loosely with foil and bake for 15 minutes, until heated through and cheese is melted.
Remove foil and bake an additional 5–10 minutes until tops are golden brown.
Meanwhile, prepare au jus according to package directions.
Slice sliders and serve warm with au jus for dipping.