Preheat your oven to 350°F (175°C) and line a half sheet pan with heavy-duty foil, spraying it with nonstick cooking spray.

Sauté the diced yellow onions in a skillet over medium heat with olive oil for about 10 minutes until tender and slightly browned.

In a large mixing bowl, combine the sautéed onions, ground beef, bread crumbs, beaten eggs, whole milk, and all spices, mixing gently.

Shape the meat mixture into a log on the prepared baking sheet, flattening the top slightly.

In a small bowl, whisk together the remaining ketchup and brown sugar and spread the glaze over the meatloaf.

Bake the meatloaf in the oven, covered loosely with foil, for 45 minutes to 1 hour, until the internal temperature reaches 160°F (71°C).

Remove the meatloaf from the oven and let it rest, covered, for 10-15 minutes before slicing.

Slice the meatloaf into thick pieces, garnish with fresh parsley and serve warm.