Step 1

In a medium bowl, add the ketchup, the light brown sugar, 2 tablespoons of the onions, the apple cider vinegar, and 1/2 teaspoon of the black pepper and whisk well to combine. Set it aside.

Step 2

In a container of a 6-quart or larger slow cooker, add a layer of aluminum foil on the bottom and up the sides of the container so there is a little overhang and lightly coat it with nonstick cooking spray.

Step 3

In a large bowl, add the ground beef, the remaining onions, the stuffing mix, the milk, the eggs, 2 tablespoons of the glaze mixture, the salt, and the remaining black pepper and with your clean hands, mix until just combined. Be careful not to overmix.

Step 4

Form the meatloaf mixture into an oval-like shape and place it into the prepared slow cooker.

Step 5

Evenly add 1/2 cup of the glaze mixture over the top of the meatloaf mixture.

Step 6

Cover the slow cooker and cook until the beef reaches an internal temperature of 145 degrees F, about 6 hours on low or about 3 hours on high.

Step 7

Preheat the oven broiler.

Step 8

Using the foil overhang, carefully lift the meatloaf from the slow cooker to an 18x26-inch baking sheet.

Step 9

Evenly top the cooked meatloaf with 2/3 cup of the glaze mixture.

Step 10

Broil the meatloaf until the glaze mixture is sticky and bubbly, about 2-3 minutes.

Step 11

Transfer the broiled meatloaf from the oven to a wire rack and let it rest for 5 minutes.

Step 12

Drizzle with the remaining glaze mixture.

Step 13

Garnish with the chopped parsley and serve.