Preheat your oven to 375°F (190°C).

In a skillet over medium heat, add olive oil and sauté diced onion for 4-5 minutes, then add minced garlic and sauté for another 2-3 minutes.

In a small mixing bowl, blend together ketchup, brown sugar, Dijon mustard, and balsamic vinegar for the glaze.

In a large mixing bowl, combine dried breadcrumbs with milk and let it sit for a minute. Then add sautéed onion and garlic, eggs, Worcestershire sauce, Italian seasoning, salt, black pepper, and garlic powder. Mix gently.

Transfer the meat mixture into a lightly oiled loaf pan, smoothing it out evenly.

Bake in the preheated oven for 45 minutes without the glaze.

Brush the glaze over the cooked meatloaf and return it to the oven. Bake for an additional 15-20 minutes until the internal temperature reaches 160°F (71°C).

Let the meatloaf rest for 5-10 minutes before slicing and serving.