Preheat the oven to 375°F (190°C) and line a baking sheet with parchment.
Mix ground beef, breadcrumbs, Parmesan, egg, garlic, onion powder, smoked paprika, salt, and pepper in a large bowl until just combined. Shape into 12 meatballs.
Heat olive oil in a skillet over medium-high, sear the meatballs on all sides for about 5 minutes, then transfer to the baking sheet.
Bake for 12–15 minutes until cooked through (165°F / 74°C).
Meanwhile, warm the bourbon BBQ sauce over low heat. Toss the cooked meatballs in the sauce.
Toast the hoagie rolls, fill each with three saucy meatballs, sprinkle with shredded cheese, and top with chopped bacon.
Broil for 1–2 minutes until the cheese is bubbly. Serve hot with extra sauce if desired.