Preheat oven to 375°F (190°C). Line a baking sheet with parchment paper.
In a large bowl, combine ground beef, egg, breadcrumbs, salt, pepper, garlic powder, onion powder, Italian seasoning, and parsley. Mix until just combined.
Place the meat mixture on the prepared baking sheet and flatten it into a rectangle, about 1/2 inch thick.
Sprinkle the center with 1 cup shredded mozzarella, leaving a border around the edges.
Carefully roll the meat into a loaf, sealing the edges to enclose the cheese.
Top the meatloaf with marinara sauce and the remaining 1/2 cup mozzarella cheese.
Bake for 45–50 minutes, or until the internal temperature reaches 160°F (71°C).
Let it rest for 5–10 minutes before slicing and serving.