In a large bowl, combine the ground beef, ground turkey, breadcrumbs, Parmesan cheese, parsley, beaten egg, garlic, onion powder, oregano, salt, and black pepper. Mix until well combined.
On a clean surface, shape the meat mixture into a large rectangle, approximately 1-inch thick. Use your hands to flatten it out.
Place the mozzarella sticks in the center of the rectangle, leaving some space at the edges.
Carefully roll the meat mixture over the cheese, tucking in the sides to enclose the mozzarella. Shape it into a loaf.
Transfer the meatloaf to a baking dish. Pour the marinara sauce evenly over the top and drizzle with olive oil.
Bake in the preheated oven for about 50-60 minutes, or until the internal temperature reaches 160°F (70°C) and the meatloaf is cooked through.
Let the meatloaf rest for 10 minutes before slicing to allow the cheese to set slightly.
Notes
Slice the meatloaf and arrange it on a serving platter. Garnish with additional fresh parsley and serve with extra marinara sauce on the side for dipping.