Preheat the oven to 350°F (175°C). Spray a large loaf pan (6½ x 10 inches) with nonstick cooking spray. Set aside.

Prepare the meat mixture: In a large bowl, combine the ground beef, ground pork, beaten eggs, Parmesan cheese, parsley, salt, and pepper. Mix together until just combined.

Combine the milk mixture: In a medium bowl, combine the milk, breadcrumbs, garlic, and onion. Add the milk mixture to the meat mixture, being careful not to overwork the ingredients.

Form the meatloaf: Add the meat mixture to the prepared loaf pan, pressing the meat in tightly to form an even shape.

Make the glaze: In a separate bowl, combine the barbecue sauce and grape jam. Mix well.

Bake the meatloaf: Spread half of the BBQ glaze mixture over the top of the meatloaf. Bake for 40 minutes.

Finish baking: After 40 minutes, spread the remaining glaze over the meatloaf. Bake for an additional 20 minutes, or until the internal temperature of the meatloaf reaches 160°F (71°C).

Rest and serve: Allow the meatloaf to rest for about 5 minutes before cutting and serving.