Brown the Pork: Heat the vegetable oil in a large frying pan over medium-high heat. Add the pork mince and cook, breaking it up with a wooden spoon, until deeply golden with crispy edges.
Add the Aromatics: Add the onion, garlic, ginger and Chinese five spice. Cook for another 2–3 minutes, until the onion begins to soften and the garlic and ginger are fragrant.
Add the Sauce and Vegetables: Whisk together the black bean sauce, light soy sauce, dark soy sauce and cider vinegar. Pour the sauce into the pan, then add the carrot and bell pepper. Toss everything together and simmer for 2–3 minutes, leaving the vegetables slightly crisp. Remove from the heat and stir through the juice of ½ lime.
Make the Peanut Sauce and Serve: If using, whisk together the peanut butter, soy sauce and sriracha, adding water 1 tablespoon at a time until you have a drizzling consistency. Spoon the pork into the lettuce cups and top with the peanut sauce, chopped peanuts, spring onion and coriander. Serve with lime wedges alongside.