Creating Stuffed Italian Meatloaf is a straightforward process that delivers incredible results. Follow these steps to make it:

1. Preheat the Oven: Set your oven to 375°F (190°C) to prepare for baking.
2. Prepare the Meat Mixture: In a large bowl, combine the ground beef, ground pork, breadcrumbs, Parmesan cheese, parsley, garlic, onion, eggs, oregano, salt, and black pepper. Mix until well incorporated.
3. Prepare the Stuffing: In another bowl, combine the shredded mozzarella, chopped bell peppers, and chopped spinach (if using). Mix well.
4. Shape the Meatloaf: Lay a large sheet of plastic wrap on a clean surface. Place the meat mixture onto the wrap and shape it into a rectangle, about 1 inch thick.
5. Add the Stuffing: Spoon the mozzarella mixture down the center of the meat rectangle, leaving space on the edges.
6. Roll It Up: Using the plastic wrap, carefully lift the edges to roll the meat over the filling. Shape it into a loaf and place it seam-side down in a greased baking dish.
7. Top with Marinara: Spread some marinara sauce over the top of the meatloaf for added flavor and moisture.
8. Bake: Place the meatloaf in the preheated oven and bake for 45-50 minutes or until it reaches an internal temperature of 160°F (70°C).
9. Rest: Once done, remove the meatloaf from the oven and let it rest for 10-15 minutes to allow the juices to redistribute.
10. Slice and Serve: Carefully slice the meatloaf and serve with additional marinara sauce if desired.

Following these steps will guide you in crafting this incredible meal effortlessly and effectively.