Preheat the oven to 375°F.
In a skillet, heat olive oil over medium heat. Add sliced onions and green peppers, sautéing until softened, about 5 to 7 minutes.
Add the thinly sliced steak to the skillet, sprinkle with garlic powder, salt, and pepper. Cook until the steak is browned, approximately 5 minutes.
Cut the slider rolls in half horizontally. Place the bottom halves on a baking sheet.
Distribute the steak, onions, and peppers evenly over the bottom halves of the rolls. Top each with a half slice of provolone cheese.
Place the top halves of the rolls onto the sliders.
Brush the tops of the rolls with melted butter.
Bake in the preheated oven for 10 to 15 minutes, or until the cheese is melted and the rolls are lightly toasted.
Serve warm.