Preheat the oven to 350°F and lightly coat a 9x5-inch loaf pan with cooking spray. In a large mixing bowl, combine the ground turkey, ground beef, breadcrumbs, eggs, and all dried herbs. Incorporate the garlic, grated onion, salt, and pepper, followed by the Parmesan cheese. Using your hands, gently mix until just combined, being cautious not to overwork the mixture to maintain a light texture.

Transfer the mixture into the prepared loaf pan, pressing it evenly while shaping a gently domed top. Spread the marinara sauce evenly across the surface, then top with shredded Italian cheese and a generous sprinkle of fresh parsley.

Place the loaf pan on a baking sheet to catch any drippings. Bake for approximately 55 minutes or until the internal temperature reaches 155°F. Remove from the oven when done.

To serve, slice the meatloaf or cut into thick squares. Optionally, top with additional sauce and cheese, and return briefly to the oven to melt the cheese. Garnish with more parsley before serving.