Prepare the pork: Pat the pork neck dry with paper towel and season generously with salt, black pepper, and smoky BBQ spice, rubbing the spices into the meat.
Sear the pork: Heat olive oil in a large pan over medium-high heat. Sear the pork neck on all sides until nicely browned, about 2-3 minutes per side. This step adds depth of flavour but can be skipped if time is limited.
Slow cook the pork: Transfer the seared pork neck to a slow cooker. Add the bourbon whisky and beef stock, ensuring the liquid covers at least half of the meat. Cover and cook on high for 3-4 hours or on low for 6-8 hours, until the pork is tender and easily shreds with a fork.
Make the sauce: While the pork is cooking, prepare the sweet and spicy sauce by whisking together the hoisin sauce, soy sauce, honey, tomato ketchup, sesame oil, chilli sauce (if using), salt and black pepper in a bowl. Set aside until needed.
Shred and coat: Once the pork is cooked, remove it from the slow cooker and let it cool slightly. Reserve ½ cup of the cooking liquid. Using two forks, shred the pork into bite-sized pieces. Pour the prepared sauce over the shredded pork and toss well to coat evenly. If the mixture seems dry, add a few tablespoons of the reserved cooking liquid.
Warm the pork: Return the sauced pork to the slow cooker on low for 10-15 minutes to warm through and allow the flavours to meld, or warm it gently in a pan over low heat.
Assemble and serve: Arrange the lettuce cups on a serving platter. Fill each cup with a generous portion of the sweet and spicy pork. Top with chopped spring onions, toasted sesame seeds, and crispy fried noodles or toasted peanuts.