Prepare the Sauce: In a small bowl, whisk together all the sauce ingredients: soy sauce, hoisin sauce, rice vinegar, and toasted sesame oil. In a separate tiny bowl, mix the cornflour with 1 tablespoon of water to create a slurry. Set both aside.

Sauté the Aromatics: Heat the vegetable oil in a large frying pan or skillet over a medium-high heat. Add the finely diced onion and cook for 3-4 minutes, until it softens and becomes translucent. Add the minced garlic and grated ginger and cook for another minute until fragrant.

Brown the Mince: Add the chicken mince to the pan. Use a wooden spoon or spatula to break it up into small pieces. Cook for 5-7 minutes, stirring occasionally, until the chicken is fully cooked through and starting to brown slightly. This browning step adds a huge amount of flavour.

Add the Vegetables: Stir in the finely diced carrot, water chestnuts, and the white parts of the spring onions. Cook for another 2-3 minutes, just to soften the carrots slightly. We still want to retain that lovely crunch from the water chestnuts.

Pour in the Sauce: Give your sauce mixture a quick whisk again and pour it into the pan with the chicken. Stir everything together to coat well. Bring the mixture to a gentle simmer.

Thicken the Filling: Pour in the cornflour slurry and stir continuously. Let the sauce simmer and bubble for 1-2 minutes. You'll see it thicken into a lovely glaze that clings to the mince. I find that this is the most important step for getting the consistency just right.

Finish and Serve: Turn off the heat and stir in the green parts of the spring onions. Transfer the filling to a serving bowl. Arrange your clean, dry lettuce leaves on a platter alongside the filling. Let everyone assemble their own fresh wraps, adding garnishes like chopped peanuts or coriander if you like.