Preheat the oven to 350°F (175°C) and line a sheet pan with parchment paper or lightly grease a small loaf pan.

Heat the olive oil or butter in a skillet over medium heat, add the diced onion, and cook for 3–4 minutes until softened.

Add the Italian seasoned bread crumbs to the skillet with the warm onions, stir to combine, and let the mixture sit for a few minutes so the bread crumbs can begin to soften.

Transfer the onion and breadcrumb mixture to a large bowl and add the ground beef, egg, milk, ketchup, Worcestershire sauce, garlic powder, onion powder, salt, black pepper, and grated Parmesan cheese, then mix gently just until combined.

Shape the mixture into a loaf and place it on the prepared sheet pan or loosely shape it inside a loaf pan without pressing it firmly into the bottom.

Stir together the ketchup, brown sugar, and Worcestershire sauce in a small bowl and spread about half of the glaze evenly over the top of the meatloaf.

Bake for 35 minutes, remove from the oven, spread the remaining glaze over the top, and return to the oven for 15 minutes or until the internal temperature reaches 160°F (71°C).

Let the meatloaf rest for 5–10 minutes before slicing and serving