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

Heat the olive oil in a large skillet over medium-high heat. Add the onion, bell pepper, and mushrooms, and cook for 5 to 6 minutes until softened.

Add the ground beef to the skillet and cook, breaking it up with a spoon, until browned and fully cooked, about 6 to 8 minutes. Drain excess grease if needed.

Stir in the garlic, Worcestershire sauce, salt, black pepper, garlic powder, and onion powder. Cook for 1 minute more, then remove from heat.

Place the bottom halves of the slider buns in the prepared baking dish. Spoon the beef mixture evenly over the buns, then layer the provolone cheese on top.

Add the top halves of the buns. Brush the tops with melted butter and sprinkle with sesame seeds if using.

Bake for 12 to 15 minutes, or until the cheese is melted and the tops are lightly golden.

Remove from the oven, slice if needed, and serve warm.