Preheat the oven to 350°F. In a small bowl add the canned tomato sauce and brown sugar together. Mix until combined and then set it aside.
In a large bowl, add all of the meatloaf ingredients (ground beef, diced onion, diced bell pepper, diced celery, Italian seasoning, salt, garlic and onion powder, black pepper, breadcrumbs, milk, beaten egg, and ¼ cup of the meatloaf sauce). Use a spatula and your hands to mix all of the ingredients together until evenly combined. Be careful not to overmix! You can also wear food safe disposable gloves if you prefer.
Place the meat mixture in a baking dish. Shape the meat into a loaf that’s about 8-inches long and 4-inches wide. Loosely cover the baking dish with aluminum foil.
Bake in the oven for 30 minutes. After 30 minutes, remove the meatloaf from the oven and remove the foil. Evenly pour the rest of the meatloaf sauce over the meatloaf. Then return the dish to the oven, uncovered, and bake an additional 30 minutes or until the internal temperature reaches 165°F.
Allow the meatloaf to rest for 10 minutes before slicing. Serve warm with your favorite sides.