This recipe comes straight from the blog Quick n' Easy Recipes.
8 oz. thinly sliced roast beef (good quality from the deli)
8 slices provolone cheese
2 large green bell peppers (I used one green and one red)
1 medium sweet onion, thinly sliced
6 oz. baby bella mushrooms, sliced
2 Tbl butter
2 Tbl olive oil
1 Tbl garlic, minced
Salt and Pepper – to taste
Preheat oven to 400F
Slice peppers in half lengthwise, remove ribs and seeds. Line the inside of each pepper with a slice of provolone cheese.
Saute sliced onions and mushrooms over medium heat with butter, olive oil, minced garlic and a little salt and pepper. Saute until onions and mushroom are nice and caramelized. About 20-25 minutes. Remove onions/mushrooms from heat.
Slice roast beef into thin, bite-sized strips and add to the onion/mushroom mixture.
Top each pepper with another slice of provolone cheese.