Preheat oven to 350°F (175°C). Slice the entire pack of slider buns in half horizontally, keeping the top and bottom halves intact. Place the bottom half in a 9×13-inch baking dish.

Heat 1 tablespoon oil in a large skillet over medium heat. Add diced onions and bell pepper. Sauté, stirring occasionally, until soft and golden, about 5–7 minutes. Add garlic and cook for another 30 seconds until fragrant.

Add ground beef to the skillet. Break it up with a spatula and cook until browned and no longer pink, about 5–8 minutes. Drain excess fat if needed.

Sprinkle in Worcestershire sauce, salt, and pepper. Stir well to combine. Taste and adjust seasoning if needed.

Evenly spoon the beef mixture over the bottom half of the buns. Layer provolone slices over the beef, overlapping for full coverage.

Place the top half of the buns over the filling.

In a small bowl, mix melted butter and garlic powder. Brush this mixture generously over the tops of the buns.

Cover the baking dish tightly with foil. Bake for 15 minutes, then remove the foil and bake another 5–7 minutes until the tops are golden and the cheese is melted.

Let the sliders cool for 5 minutes, then cut along the bun lines. Serve hot.