Directions:

Preheat oven to 400◦. Slice peppers in half lengthwise removing ribs and seeds. Slice onions and mushrooms. Sauté until onions and mushrooms are nice and caramelized. About 25-30mins. Slice roast beef into thin strips and add onion/mushroom mixture. Cook 5-10mins. Line the inside of each pepper with provolone cheese and fill each with meat mixture until they are overflowing. Top each pepper with another slice of provolone cheese and bake for 15-20mins until cheese is golden brown.