Preheat the oven to 375°F (190°C) and line a baking sheet or 9x5 inch loaf pan with parchment paper.
In a large bowl, whisk the eggs, then add milk, breadcrumbs, chopped onion, garlic powder, salt, and black pepper. Let sit for 5 minutes.
Gently mix the ground beef into the breadcrumb mixture until just combined. Do not overmix.
Shape the beef mixture into a 9x5 inch loaf on the prepared baking sheet or press evenly into the loaf pan. Bake for 40 minutes.
While the meatloaf bakes, whisk together ketchup, brown sugar, and white vinegar in a small bowl to create the glaze.
Remove the meatloaf from the oven and spread the tomato glaze evenly over the top and sides. Return to the oven and bake for an additional 15-20 minutes, or until the internal temperature reaches 160°F (71°C).
Let the meatloaf rest for 10 minutes before slicing. Garnish with chopped fresh parsley and serve alongside mashed potatoes and steamed green beans.