01 - Preheat oven to 375°F (190°C). Line a loaf pan with parchment paper or lightly grease it.
02 - In a large bowl, combine breadcrumbs and milk. Allow to sit for 2 minutes to soften.
03 - Add ground chicken, egg, onion, garlic, parsley, oregano, paprika, salt, and pepper to the breadcrumb mixture. Combine gently until just incorporated; avoid overmixing.
04 - Spread half of the chicken mixture into the prepared loaf pan. Press down lightly to form a shallow indent in the center.
05 - Distribute mozzarella and cheddar cheese evenly over the indent, ensuring it stays away from the pan edges.
06 - Cover with the remaining chicken mixture, pressing and sealing the edges to fully enclose the cheese.
07 - Brush the top surface with tomato sauce or ketchup, followed by a drizzle of olive oil.
08 - Bake for 45–50 minutes, or until an instant-read thermometer registers an internal temperature of 165°F (74°C) and the exterior is golden.
09 - Allow the meatloaf to rest for 10 minutes before slicing and serving.