Preheat your oven to 375°F (190°C) and prepare a baking sheet or loaf pan lined with parchment paper.

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

In a separate bowl, combine the mozzarella cheese, Parmesan cheese, and optional spinach. Mix well to create a creamy filling.

Flatten the meat mixture onto parchment paper into a rectangle about 1-inch thick.

Spread the cheesy filling evenly over the meat mixture, leaving a small border around the edges.

Roll the meat mixture tightly using the parchment paper and seal the edges.

Place the rolled meatloaf seam-side down onto your prepared baking sheet or loaf pan.

Bake for 45-50 minutes until the internal temperature reaches 160°F (71°C).

In the last 10 minutes, top the meatloaf with marinara sauce and allow it to heat through.

Let the meatloaf rest for 10 minutes before slicing to allow the juices to redistribute.