Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the ground beef, breadcrumbs, chopped onion, milk, eggs, salt, pepper, garlic powder, onion powder, and thyme (if using). Mix until well combined.
Transfer the meat mixture into a baking dish or loaf pan, forming it into a loaf shape.
In a separate bowl, mix together the ketchup, brown sugar, and Worcestershire sauce to make the glaze. Spread the glaze evenly over the top of the meatloaf.
Bake the meatloaf in the preheated oven for about 60 minutes, or until the internal temperature reaches 160°F (70°C).
Remove the meatloaf from the oven and let it rest for 10 minutes before slicing and serving.