1. Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper or foil, and optionally place a wire rack on top.

2. Heat a small amount of olive oil in a skillet over medium heat. Add the finely diced yellow onion and minced garlic. Sauté for 5-7 minutes until the onion is translucent and the garlic is fragrant. Allow to cool slightly.

3. In a large mixing bowl, gently combine the ground beef, cooled onions and garlic, eggs, panko breadcrumbs, milk, Parmesan cheese, parsley, Worcestershire sauce, salt, and pepper. Mix with your hands until just combined (1-2 minutes), being careful not to overmix.

4. Transfer the meat mixture to the prepared baking sheet. Shape into a loaf approximately 9×5 inches and 2-3 inches high.

5. In a small bowl, whisk together the ketchup, brown sugar, and apple cider vinegar until smooth.

6. Bake the meatloaf for 45 minutes.

7. Remove the meatloaf from the oven. Spread about two-thirds of the glaze evenly over the top and sides of the loaf. Return to the oven and bake for an additional 15-20 minutes, until an instant-read thermometer inserted into the center registers 160°F (71°C).

8. Remove from oven and let the meatloaf rest for 10-15 minutes before slicing. Serve with remaining glaze if desired.