Preheat the oven to 350°F (177°C). Lightly grease a 9x5-inch loaf pan or line it with parchment paper.
In a large bowl combine ground beef, breadcrumbs, chopped onion, beaten eggs, milk, salt, pepper, and garlic powder. Mix gently until just combined—do not overmix.
Transfer the meat mixture to the prepared loaf pan and shape into a loaf, smoothing the top with a spatula.
In a small bowl whisk together the brown sugar, ketchup, and Worcestershire sauce to make the glaze.
Spread about half of the glaze evenly over the top of the meatloaf before baking, reserving the rest for later.
Bake in the preheated oven for 50 to 60 minutes, or until the internal temperature reaches 160°F (71°C). About 10 minutes before the end of baking, brush the remaining glaze over the top.
Remove the meatloaf from the oven and let it rest in the pan for 10 minutes to set. Then transfer to a cutting board and slice.
Serve warm with your favorite sides such as mashed potatoes or steamed vegetables.
Notes
Let the meatloaf rest before slicing to keep slices intact. Leftovers keep well refrigerated for up to 3 days.