Preheat your oven to 350°F (175°C) and prepare a baking sheet with foil and nonstick spray.

In a medium skillet, sauté diced yellow onions in olive oil for about 10 minutes until golden brown.

In a mixing bowl, combine ground beef, bread crumbs, beaten eggs, whole milk, salt, black pepper, onion powder, garlic powder, Italian seasoning, half of the ketchup, Worcestershire sauce, and parsley. Mix until just combined.

Shape the mixture into a log on the baking sheet, about 8-10 inches long, and flatten the top slightly.

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

Bake the meatloaf in preheated oven for 45 minutes to 1 hour, until the internal temperature reaches at least 160°F (71°C).

Let the meatloaf rest for 10 to 15 minutes before slicing and serving.