01 -
Line a rimmed baking sheet with parchment paper or foil for easier cleanup, and preheat oven to 175°C (350°F).
02 -
Set a medium skillet over medium heat. Add 1 tsp olive oil and chopped onion, then saute, stirring occasionally, until softened and golden, about 5-7 minutes. Transfer to a plate to cool.
03 -
In a large bowl, combine ground beef, cooked onions, eggs, garlic, ketchup, parsley, breadcrumbs, milk, salt, Italian seasoning, and black pepper. Mix just until well combined using your hands. Avoid overmixing to prevent a dense texture.
04 -
Transfer meat mixture to the prepared baking sheet, shaping it into a loaf approximately 20 cm long, 10 cm wide, and 7.5 cm tall (8x4x3 inches). Bake uncovered at 175°C (350°F) for 40 minutes.
05 -
In a small bowl, combine ketchup, white vinegar, brown sugar, garlic powder, and onion powder. Stir until smooth.
06 -
Spread the prepared sauce evenly over the meatloaf. Return to the oven and bake for an additional 20 minutes or until the internal temperature reaches 71°C (160°F) on an instant-read thermometer. Allow the meatloaf to rest for 10-15 minutes before slicing.