In a large sauté pan over low-medium heat, add butter, olive oil, garlic, mushrooms onions and a little salt and pepper. Sauté until onions and mushroom are nice and caramelized. About 30 minutes.
Preheat oven to 400°
Slice roast beef into thin strips and add to the onion/mushroom mixture. Allow to cook 5-10 minutes.
Line the inside of each pepper with a slice of provolone cheese. Fill each pepper with meat mixture until they are nearly overflowing. Top each pepper with another slice of provolone cheese.
Bake for 15-20 minutes until the cheese on top is golden brown.
Prep Time – 15 Minutes
Makes Servings: 4