Preheat the oven to 350°F (175°C)
Chop the onion and green bell pepper
Heat a large skillet over medium heat
Cook the onion and bell pepper for 5-7 minutes until slightly softened, then remove to a plate
Add the shaved steak and steak seasoning to the skillet
Cook until the steak is browned, stirring as it cooks
Return the peppers and onions to the skillet and cook for an additional 3-5 minutes
Slice the slider rolls in half, keeping the top and bottom halves intact
Place the bottom half of the rolls into a casserole dish
Layer a little over half of the steak, pepper, and onion mixture onto the rolls
Place 4 slices of provolone cheese over the mixture
Add the remaining steak mixture on top
Tear the remaining cheese slices and tuck them in between the meat
Cover with the top half of the slider rolls
Brush the melted butter over the top of the rolls
Bake for 10-15 minutes until the cheese is melted and the tops are golden brown
Serve warm and enjoy!