Preheat oven to 350°F. Spray a 9x9-inch baking dish with nonstick cooking spray.
In a large bowl, combine the ground beef, ground pork, beaten egg, cheese, parsley, salt, and pepper. Mix until just combined.
In a medium bowl, combine the milk, breadcrumbs, garlic, and onion.
Add milk mixture to the meat mixture, careful not to overwork ingredients.
Greasing hands before starting, form the mixture into desired-size meatballs. (We used a heaping 2-tablespoon scoop for each meatball.) Place into the prepared baking dish.
Place in the oven and roast for about 20 minutes, or until the meatballs are crisp on the outside.
Remove the meatballs from the oven. Carefully discard most of the grease.
In a medium bowl, combine the barbecue sauce, honey, and grape jelly. Pour the sauce over the partially cooked meatballs.
Cover the dish with aluminum foil. Place the meatballs back into the oven to bake for an additional 20-25 minutes, or until the meatballs are cooked to an internal temperature of 165°F. (Cooking times may vary, depending on the size of the meatballs.)
Serve warm.