In a skillet, cook shaved steak over medium heat until no longer pink, set aside.
In same skillet, over medium heat add olive oil & butter then saute the onions, garlic, & mushrooms for 5-7 minutes until lightly browned. Add in the shaved steak & mix.
Line a baking sheet with foil and spray with PAM or brush with olive oil.
Stuff bell peppers with steak mixture and top with a slice of provolone cheese, place on baking sheet.
Bake for 15-20 minutes until cheese starts to brown.