01 -
Set the oven to 190°C (375°F) and allow it to fully preheat.
02 -
In a large bowl, combine ground beef, ground Italian sausage, finely chopped onion, minced garlic, bread crumbs, eggs, grated Parmesan, Italian seasoning, and chopped parsley. Pour in milk and season with salt and black pepper. Mix thoroughly until all ingredients are evenly incorporated.
03 -
On a lined baking tray, shape the meat mixture into a rectangular loaf approximately 23×30 cm in size.
04 -
Create a cavity in the center of the formed meatloaf. Fill this well with shredded mozzarella, chopped spinach if using, and a spoonful of marinara sauce.
05 -
Carefully fold the meat around the filling, sealing the edges to enclose the stuffing completely and form a compact loaf.
06 -
Spread the remaining marinara sauce evenly over the surface of the meatloaf. Sprinkle grated Parmesan cheese on top.
07 -
Place the meatloaf in the preheated oven and bake for 45 to 55 minutes or until the internal temperature reaches 71°C (160°F).
08 -
Remove from oven and let rest for 10 minutes before slicing. Serve warm with additional marinara sauce if desired.