Step 1

Position a rack in the upper third of the oven and preheat to 375 degrees F. Mix 1/2 cup of the ketchup, the breadcrumbs, milk, eggs, parsley, and 1 tablespoon Worcestershire sauce together in a large bowl and set aside until the breadcrumbs have absorbed the liquid, about 3 minutes.

Step 2

Add the ground beef and pork, onion, garlic, 1 tablespoon salt, and 1/2 teaspoon pepper to the bowl and mix until well combined (do not overmix).

Step 3

Transfer the meat mixture to an 18-by-13-inch sheet pan (see Cook's Note) and press it into an even layer covering the entire surface. Whisk the remaining 1 1/2 cups ketchup, 1 tablespoon Worcestershire, brown sugar, cider vinegar, and chipotle powder in a small bowl. Brush the meatloaf with the sauce.

Step 4

Bake until the meat is cooked through, about 20 minutes, then turn on the broiler setting and broil until the top becomes caramelized and dark in spots, 3 to 4 minutes more, turning the pan periodically for even broiling. Let rest 5 minutes before serving.