Combine the buttermilk, bread crumbs, and garlic powder in a medium bowl. Reserve until ready to use.

In a large bowl, combine the vegetables with the meatloaf mix, buttermilk mixture, tomato paste, parsley, basil, eggs, Worcestershire sauce, salt, and 1 teaspoon of pepper.

Gently fold the ingredients together with your hands. Try to avoid squeezing the meat as much as possible while still achieving a homogenous mixture.

Press the meatloaf mixture into the prepared loaf pan. Flip the meatloaf out onto the foil-lined baking sheet.

Bake the meatloaf for 15 minutes, then brush it with about half of the glaze.

Meanwhile, prepare the glaze by combining the ketchup, tomato paste, brown sugar, honey, vinegar, Worcestershire sauce, and remaining pepper in a small bowl. Whisk to combine.