Preheat the oven to 350°F (175°C). Lightly grease a baking dish or sheet pan.

Heat the olive oil and butter in a skillet over medium heat. Add the sliced onion and cook until softened and lightly caramelized, about 8 to 10 minutes.

Stir in the Worcestershire sauce, garlic powder, and onion powder. Add the roast beef and toss just until warmed through, then remove from the heat.

In a small saucepan, combine the beef broth, soy sauce, dried thyme, salt, and black pepper. Warm over medium heat until hot, then keep on low heat for serving.

Place the bottom halves of the slider rolls in the prepared baking dish. Layer on the warm beef and onions, then top with provolone cheese and the slider tops.

Cover the dish with foil and bake for 10 minutes. Remove the foil and bake for 5 more minutes, or until the cheese is melted and the tops are lightly golden.

Slice and serve warm with the hot beef broth for dipping.