Preheat your oven to 375°F (190°C).

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

In a separate bowl, mix mozzarella cheese, Parmesan cheese, and spinach until evenly combined.

On parchment paper, flatten the meat mixture into a rectangle. Spoon the cheese filling onto the center, spread it evenly, then roll the meat around the filling tightly.

Transfer the assembled meatloaf seam-side down onto a baking sheet and bake for 45 to 50 minutes until golden brown and internal temperature reaches 160°F (71°C).

About 10 minutes before the meatloaf is done, remove it and spoon marinara sauce over the top, then return to bake.

Once done, let the meatloaf rest for 10 minutes, slice, and serve with additional marinara on the side.