Preheat your oven to 350°F (175°C) and prepare a baking sheet by lining it with parchment paper or greasing it.

In a medium skillet, add olive oil and sauté the chopped onion and minced garlic over medium heat until translucent, about 5 minutes. Set aside to cool slightly.

In a large mixing bowl, combine ground beef, breadcrumbs, grated Parmesan, parsley, basil, sautéed onion and garlic, eggs, marinara sauce, Italian seasoning, salt, and pepper. Mix gently until just combined.

Transfer the meat mixture onto parchment paper and shape it into a rectangle about 1 inch thick.

Sprinkle the shredded mozzarella over the meatloaf rectangle, leaving a border. Add the optional pepperoni or prosciutto on top.

Carefully roll the meat mixture away from you using the parchment paper, forming a log shape and enclosing the filling. Place seam-side down on the baking sheet.

Press the loaf gently to shape it and spoon additional marinara sauce over the top, allowing it to drip down the sides.

Bake for about 60 minutes, or until the internal temperature reaches 160°F (70°C). The exterior should be browned and the sauce bubbly.

Let the meatloaf rest for 15-20 minutes before slicing.

Slice into thick pieces and serve with garlic bread and a fresh salad.