Preheat your oven to 350°F (175°C).
In a small bowl, mix together the mayonnaise, Dijon mustard, Worcestershire sauce, garlic powder, onion powder, salt, and pepper. Set aside.
Slice the slider buns in half horizontally and place the bottom halves in a baking dish.
Spread the prepared sauce evenly over the bottom halves of the buns.
Layer the roast beef evenly over the sauce, followed by the provolone cheese slices.
Place the top halves of the buns over the cheese.
In a small bowl, mix the olive oil with a pinch of garlic powder and brush it over the top of the slider buns.
Cover the baking dish with aluminum foil and bake for 15 minutes.
Remove the foil and bake for an additional 10 minutes, or until the cheese is melted and the tops are golden brown.
Remove from the oven, garnish with chopped parsley if desired, and serve warm.