Philly Cheese Steak Stuffed Bell Peppers

I found this recipe on Pinterest and we love it!  It's not only good in the cool weather, but also light for the warmer weather.

Ingredients

8 oz thinly sliced roast beef
8 slices provolone cheese
2 large green bell peppers
Chopped onion
1 6.5 oz can mushrooms and stems (or chopped fresh mushrooms)
2 tbs butter
2 tbs olive oil
1-3 cloves minced garlic
Salt and pepper to taste

Preparation

1. Slice peppers in half lengthwise, remove ribs and seeds.
2. Saute onions and mushrooms over medium heat with butter, olive oil, garlic, and salt and pepper.  Saute until caramelized, 25 - 30 minutes.
3. Preheat oven to 400*
4. Slice roast beef into thin strips and add to the onion mushroom mixture.  Allow to cook 5-10 minutes.
5. Load the inside of each pepper with a slice of cheese.
6. Fill each pepper with 1/4 of the meat mixture.
7. Top each pepper with another slice of cheese.
8. Bake 15-20 minutes until the cheese on top is golden brown.
9. Serve hot.