Preheat your oven to 200°C (400°F) and line a baking sheet with foil.

In a skillet, add a drizzle of olive oil and sauté the finely diced onion and minced garlic for 3–5 minutes.

Transfer the sautéed onion and garlic to a mixing bowl, then add ground chicken, breadcrumbs, milk, Parmesan, egg, parsley, Italian seasoning, and salt; mix gently.

Shape two-thirds of the mixture into a loaf on the baking sheet, create a well in the center, and fill with mozzarella strings; cover with remaining mixture.

Top the meatloaf with marinara sauce, spreading it evenly.

Bake in the preheated oven for about 45 minutes until browned and cooked to an internal temperature of 74°C (165°F).

Prepare the topping by mixing panko, melted butter, and additional Parmesan; set aside.

After 45 minutes, add the topping and bake for an additional 15–20 minutes until the topping is golden and cheese bubble.

Let the meatloaf rest for 10 minutes before slicing.

Serve hot, perhaps with mashed potatoes or a salad.