Step 1: Preheat your oven to 375°F (190°C). Lightly grease a loaf pan (9x5 inch) or line a baking sheet with parchment paper.
Step 2: In a large mixing bowl, combine the ground chicken, breadcrumbs, Parmesan cheese, milk, egg, minced garlic, chopped parsley, onion powder, salt, and black pepper.
Step 3: Mix gently with your hands until all ingredients are just combined. Be careful not to overmix, as this can lead to a tough meatloaf.
Step 4: Transfer the mixture to the prepared loaf pan, or form it into a loaf shape on the parchment-lined baking sheet.
Step 5: In a small bowl, whisk together the ketchup, brown sugar, apple cider vinegar, and Dijon mustard for the glaze.
Step 6: Spread about half of the glaze evenly over the top of the meatloaf.
Step 7: Bake for 40 minutes.
Step 8: Remove the meatloaf from the oven, spread the remaining glaze over the top, and return to the oven.
Step 9: Continue baking for another 15-20 minutes, or until the internal temperature reaches 165°F (74°C) using a meat thermometer. The glaze should be slightly caramelized.
Step 10: Once done, remove the meatloaf from the oven and let it rest in the pan for 10-15 minutes before slicing and serving. This allows the juices to redistribute, ensuring a moist and tender result.