How To Make Philly Cheesesteak Stuffed Peppers:

1. Step 1: Preheat Oven and Prepare Peppers: Preheat the oven to 350∘F. Slice the tops off of the 3 bell peppers and deseed them. Lightly oil the inside of the peppers and a small baking dish.
2. Step 2: Cook Beef and Onion: Place the 1 lb. ground beef and 1 chopped onion in a skillet over medium-high heat. Sauté until the beef is browned and the onion has softened. Drain any excess grease.
3. Step 3: Add Mushrooms and Seasoning:Stir in the 8 oz. chopped mushrooms. Mix in the 1 cup beef broth, 1 tbsp. Worcestershire sauce, 2 tbsp. ketchup, and salt and pepper to taste.
4. Step 4: Simmer Filling: Bring the mixture to a simmer and cook until the liquid is almost all absorbed and the filling is thick (about 5-7 minutes).
5. Step 5: Stuff and Top: Stuff the peppers evenly with the meat mixture. Place them upright in the prepared baking dish. Sprinkle the tops of the stuffed peppers generously with the 8 oz. shredded mozzarella cheese.
6. Step 6: Bake: Tent a piece of aluminum foil loosely over the baking dish and bake for 45 minutes, or until the peppers are tender. Remove the foil during the last 5-10 minutes if you want the cheese to brown more.
7. Step 7: Enjoy: Allow the peppers to cool slightly before serving.