Preheat your oven to 350°F (175°C) and line a baking dish with aluminum foil, lightly coating with cooking spray.

In a skillet over medium heat, melt a tablespoon of butter and sauté the chopped onion until translucent, about 5 minutes.

In a mixing bowl, combine the eggs, milk, and Italian breadcrumbs; mix well and let it sit for 5-10 minutes.

Blend the hydrated breadcrumbs with the ground beef, cooled onions, ketchup, Italian seasoning, chopped parsley, salt, and black pepper.

Transfer the mixture into the prepared baking dish, shaping it into a loaf with a slight indentation on top.

Bake the meatloaf in the preheated oven for 40 minutes, checking for an internal temperature of 160°F (70°C).

Meanwhile, mix together the topping ingredients: ketchup, brown sugar, and extra Italian seasoning.

After 40 minutes, spread the glaze over the top of the meatloaf and return it to the oven for an additional 15-30 minutes.

Once baked, let the meatloaf rest for at least 10 minutes before slicing and serving.