First, slice the tops off the bell peppers and remove seeds and membranes. I always like to trim a tiny bit from the bottom so they sit flat in the baking dish. This ensures even cooking and prevents them from tipping over.
In a skillet over medium heat, brown the ground beef, Italian sausage, and pepperoni until fully cooked. I usually drain excess fat, then stir in pizza sauce, garlic powder, oregano, salt, and pepper to create a savory filling.
Spoon the meat mixture into each bell pepper generously, filling them to the top. I like pressing it down slightly to ensure every bite has a perfect balance of meat and veggies.
Top each stuffed pepper with mozzarella and Parmesan cheese. Bake in a preheated oven at 375°F (190°C) for 25–30 minutes until peppers are tender and cheese is bubbly. I sometimes broil for the last 2–3 minutes to get a golden, slightly crisp topping.
Allow the stuffed peppers to rest for a few minutes after baking. This makes them easier to handle and helps the flavors meld together beautifully.