Preheat your oven to 350°F (175°C).
In a large bowl, combine ground beef, breadcrumbs, and chopped onion.
In a separate bowl, mix milk, egg, Worcestershire sauce, garlic powder, salt, and pepper.
Pour the wet mixture into the meat mixture and combine well.
Transfer the mixture into a loaf pan, shaping it into a loaf.
Spread ketchup evenly over the top of the meatloaf.
Bake in the preheated oven for 1 hour.
Check for doneness with a meat thermometer (should read 160°F).
Remove from oven and let it rest for 10 minutes before slicing.
Serve warm with your favorite sides.