Preheat your oven to 400°F.
In a large bowl, combine the ground beef, crumbled bacon, breadcrumbs, Parmesan cheese, parsley, egg, garlic powder, onion powder, salt, and black pepper. Mix until just combined; do not overmix.
Form the mixture into meatballs, about 1.5 inches in diameter, and place them on a baking sheet lined with parchment paper.
Bake the meatballs in the preheated oven for 20-25 minutes or until they are cooked through and browned.
In the last 5 minutes of baking, drizzle the meatballs with bourbon BBQ sauce and top each with a slice of cheddar cheese. Return to the oven until the cheese is melted.
While the meatballs are baking, warm the sub rolls in the oven for about 5 minutes.
To assemble the subs, place 3-4 meatballs in each sub roll, drizzle with extra BBQ sauce, and serve immediately.