Heat the oven to 400 degrees.
Place the cut green peppers into a 9×13 baking dish, and drizzle with 1 Tbsp of the olive oil.
Cover with tin foil and bake for 20 minutes.
Place the remaining oil in a skillet over medium high heat, and season the steak with salt and pepper to taste.
Sear the steak well on both sides, and cook until done to your liking.
Remove the steak from the heat, let rest for 5 minutes, and slice very thinly.
Add the mushrooms, red bell pepper and onion to the skillet, and saute until becoming tender.
Take the green peppers out of the oven, and fill with the steak and vegetable mixture.
Top with the shredded cheese.
Bake for 15 minutes
Enjoy