1.Preheat the oven to 350°F and prepare a baking sheet with parchment paper.
2.In a skillet, melt the butter over medium heat and sauté the onions, green peppers, and mushrooms until soft, about 5 minutes.
3.Add the sliced beef to the skillet, seasoning with salt and pepper, and cook until browned.
4.Roll out the crescent roll dough and cut it into four squares. Place a spoonful of the cooked beef mixture onto each square.
5.Top the beef mixture with mozzarella and provolone cheese, then fold the dough over to form pockets, sealing the edges. Sprinkle it with parmesan cheese.
6.Place the pockets on the prepared baking sheet and bake for 20 minutes or until golden brown.
7.Serve hot with your favorite dipping sauce.