Preheat oven to 350° F. Sauté the onions in olive oil until caramelized, add minced garlic, sauté for 1 additional minute.
Remove the onion mixture from heat, add Worcestershire sauce, salt and pepper and allow to cool to room temperature.
In a large mixing bowl, combine the ground ground beef, eggs, bread crumbs, tomato sauce and the cooled onion mixture.
Use your hands to mix the simple meatloaf mixture very well. Since this is raw meat you might wish to use disposable food prep gloves for this.
Spray a bread loaf pan with cooking spray and press the meatloaf mixture into the loaf pan, press down well to shape. Only use the bread loaf pan as a mold but not for baking.
Place parchment paper on a large baking sheet. Carefully turn loaf pan upside down onto the parchment lined baking sheet to remove meatloaf. Finish shaping the meat loaf by hand. This step will prevent a soggy meatloaf since it will be baked on the baking sheet.
Mix the meatloaf glaze ingredients,( ketchup, vinegar and brown sugar) in a small bowl. Combine well.
Pour a little over half of the glaze mixture on the entire meatloaf saving the rest for later. Spread with the back of a spoon until its evenly dispersed. Place in preheated oven and bake for about 60 minutes until juices run clear and the center temperature is 160 degrees F.
During the last 10 minutes of baking, brush the remaining glaze mixture on the top of the meatloaf. Remove from oven and slice to serve.