Heat 1 tablespoon of olive oil in a skillet over medium heat. Add 80g of finely diced onion and sauté until softened and translucent, about 5 minutes. Stir in 2 minced garlic cloves and cook for another 1-2 minutes until fragrant. Remove from heat and let cool.

In a large mixing bowl, combine 900g of ground chicken, the cooled sautéed onion and garlic, 60g of seasoned breadcrumbs, 2 teaspoons of milk, 30g of grated Parmesan cheese, 1 large egg, 2 tablespoons of chopped fresh parsley, 1 teaspoon of Italian seasoning, and ½ teaspoon of salt. Mix gently until just combined.

On a lined baking sheet, form two-thirds of the meat mixture into a rectangular shape, about 1 inch thick. Create a shallow trench down the center and place 3 slices of mozzarella cheese along this trench. Top with the remaining meat mixture, sealing the edges well.

Spread 120ml of marinara sauce generously over the meatloaf. Preheat the oven to 200°C (400°F) and place in the oven. Bake for 45 minutes, until golden and internal temperature reaches 74°C (165°F).

Prepare the topping by mixing 2 tablespoons of panko breadcrumbs, an additional 30g of grated Parmesan cheese, 20g of melted butter, and a tablespoon of chopped parsley in a small bowl. After 45 minutes, sprinkle the mixture over the meatloaf and return to bake for an additional 15-20 minutes until golden brown.

Once done, take the meatloaf out of the oven and allow it to rest for about 10 minutes. Slice before serving with sides like garlic mashed potatoes or a fresh salad.