Preheat the oven to 375°F (190°C).

In a large bowl, combine ground beef, breadcrumbs, eggs, garlic powder, onion powder, Italian seasoning, salt, and pepper. Mix gently until just combined.

In a separate bowl, combine mozzarella cheese, Parmesan cheese, and spinach (if using). Mix well.

On a sheet of parchment paper, flatten the meat mixture into a rectangle shape, scoop the cheesy filling over the center, and roll up the meat mixture carefully.

Transfer the rolled meatloaf to a baking dish seam-side down. Bake for 45-50 minutes until the internal temperature reaches 160°F (71°C).

During the last 10 minutes of baking, spoon marinara sauce over the top of the meatloaf.

Remove the meatloaf from the oven and allow it to rest for 10 minutes before slicing.

Slice and serve with additional marinara sauce if desired.