Slice Peppers in half length ways. Clean seeds out.
In a large pan over med heat, add butter, olive oil, garlic and onions, salt and pepper. Saute them till they are caramelized. Approximately 15 min.
Pre heat oven to 400 degrees.
Slice roast beef into thin strips and add it to the onion mix. Cook for 10 minutes or so.
Take 1/2 slice of provolone cheese and lay it to fit in your pepper. Fill each pepper with meat/onion mix.
Bake for 15 Min. Take out of the oven then lay the other half of the cheese across the top of each pepper bake another 5 to 8 minutes or until cheese is golden brown on top!