Cook the Beef and Vegetables:
Heat olive oil in a large skillet over medium-high heat. Add the thinly sliced steak and cook until browned, about 4–5 minutes.
Add the onions and bell peppers to the skillet. Season with garlic powder, salt, and pepper. Cook until the onions are soft and caramelized, about 5–7 minutes. Remove from heat.
Assemble the Sliders:
Preheat your oven to 350°F (175°C).
Slice the slider buns in half horizontally, keeping the bottom and top halves intact. Place the bottom halves in a baking dish or on a lined baking sheet.
Layer the cooked beef and vegetable mixture evenly over the buns. Top with slices of provolone cheese, ensuring even coverage.
Place the top halves of the slider buns over the cheese.
Add the Butter Topping:
In a small bowl, mix melted butter with garlic powder, dried parsley, and salt.
Use a pastry brush to generously brush the butter mixture over the tops of the buns.
Bake the Sliders:
Cover the sliders loosely with foil and bake for 10 minutes. Remove the foil and bake for an additional 5–7 minutes, or until the cheese is melted and the tops are golden brown.
Serve:
Remove from the oven, let cool slightly, and cut into individual sliders. Serve hot and enjoy!