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

In a skillet over medium heat, heat a tablespoon of olive oil and sauté diced yellow onions for about 10 minutes until tender and caramelized.

Combine sautéed onions with ground beef, bread crumbs, beaten eggs, whole milk, salt, black pepper, onion powder, garlic powder, Italian seasoning, half the ketchup, and Worcestershire sauce in a mixing bowl, mixing gently until just combined.

Transfer the meat mixture onto the prepared baking sheet, shaping it into a log approximately 8 inches wide.

In a small bowl, whisk remaining ketchup and brown sugar until smooth, then spread the glaze evenly over the top of the formed meatloaf.

Cover loosely with foil and bake in the preheated oven for 45 minutes to 1 hour, or until internal temperature reaches 160°F.

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