Preheat your oven to 350°F (175°C) to prepare for baking the sliders.
In a large skillet, pour the olive oil and heat it over medium heat. Add the sliced onion and bell pepper, sauté for about 5-7 minutes until tender.
Add the thinly sliced ribeye steak to the skillet with the onions and peppers. Season with garlic powder, salt, and pepper. Cook for about 5-6 minutes until the steak is browned.
Remove the skillet from heat and stir in half of the provolone cheese until melted.
Slice each slider bun in half horizontally and arrange the bottom halves in a baking dish. Spread mayonnaise on the bottom halves if using.
Spoon the steak, onion, and pepper mixture onto the bottom halves of the slider buns.
Lay the remaining provolone cheese over the filling in each slider. Place the top halves of the buns over the cheese.
Cover the baking dish with aluminum foil and bake for 10 minutes. Remove the foil and bake for an additional 5-10 minutes until the cheese is bubbly and tops are golden brown.
Remove from the oven and let cool for a few minutes before slicing into individual sliders.
Sprinkle chopped fresh parsley over the sliders for garnish.
Notes
Serve with toothpicks and a side of pickles or chips.