Preheat your oven to 375°F (190°C). Line a rimmed baking sheet with parchment paper.

In a large mixing bowl, combine the Panko breadcrumbs and milk. Let sit for 5 minutes to create a panade.

Add the beaten eggs, diced onion, minced garlic, half cup of Parmesan cheese, parsley, Italian seasoning, salt, and pepper to the breadcrumb mixture. Stir until well combined.

Crumble the ground beef into the bowl. Using your hands, gently mix until the ingredients are just combined. Do not overmix.

Transfer the meat mixture to the prepared baking sheet and shape it into a 9x5 inch loaf.

Bake in the preheated oven for 40 minutes.

Remove from the oven and top evenly with the remaining Parmesan and Mozzarella cheese.

Return to the oven and bake for an additional 10-15 minutes until the internal temperature reaches 160°F (71°C) and the cheese is bubbly and golden.

Let the meatloaf rest for 10 minutes before slicing. Garnish with additional parsley and serve.