Prepare the Lettuce and Sauce: First, carefully separate the lettuce leaves from the head, wash them, and pat them dry. The goal is to create natural 'cups'. For a guide on the best way to do this without tearing, the BBC has a good overview of how to prepare lettuce. Arrange them on a platter and set aside. In a small bowl, whisk together all the sauce ingredients: soy sauce, hoisin sauce, rice vinegar, toasted sesame oil, and honey.

Sauté the Aromatics: Heat the vegetable and sesame oil in a large frying pan or wok over a medium-high heat. Once shimmering, add the finely chopped onion and sauté for 3-4 minutes until it begins to soften and become translucent.

Add Garlic, Ginger, and Spring Onion Whites: Add the minced garlic, grated ginger, and the white parts of the spring onions to the pan. Cook for another minute, stirring constantly until fragrant. Be careful not to let the garlic burn.

Cook the Chicken: Add the chicken mince to the pan. Break it up with a wooden spoon and cook for 5-7 minutes, stirring occasionally, until it's cooked through and no longer pink. Make sure to get some nice browning on the chicken for extra flavour.

Add Water Chestnuts: Drain any excess fat from the pan if necessary. Stir in the finely chopped water chestnuts and cook for 1-2 minutes. I find this step helps them integrate into the filling nicely.

Pour in the Sauce: Pour the prepared sauce mixture over the chicken. Stir everything together well to coat the chicken evenly. Let it bubble away for 2-3 minutes, allowing the sauce to reduce and thicken slightly, clinging to the chicken.

Finish and Serve: Turn off the heat and stir in the green parts of the spring onions. Let the mixture cool for just a few minutes before serving. To serve, spoon the warm chicken filling into the prepared lettuce cups. Garnish with toasted sesame seeds, fresh coriander, and chopped peanuts if you like.