The Method

1. Prepare the chestnuts: place chestnuts flat side down on board. Use a small paring knife or kitchen scissors to make a slit crosswise over the top. Soak them in water for about 2 hours and oven roast them at 180 degrees for 30 mins until the skins split open. Let them cool enough to handle, but still warm enough to work with. Quickly peel the outer shell, then remove the inner brown membrane. You may mash up 3 of them for a more chest nutty taste to the sauce.
2. In a large pot, heat about a tablespoon of oil and add garlic, ginger and the white portions of spring onions. Stir fry until fragrant and add chicken pieces. Briefly toss around until most surfaces have browned, then add in the mushrooms and chestnuts (both whole and mashed), followed by light and dark soy sauce, chilli peppers, ground up peppercorns, star anise and mix well altogether. Pour in Shaoxing wine, chicken stock and water, followed by adding rock sugar and honey. Bring to a boil, then reduce heat to a simmer and let it cook for 35-40 minutes.
3. Drain and transfer sauce into a smaller saucepan and let it simmer on medium heat for several minutes until sauce thickens. Stir in slurry cornstarch near the end. The sauce should be thick enough to coat the back of a spoon.
4. To serve, drizzle sesame oil over and mix with chicken chestnut mushroom pieces that were drained. Place into serving bowl/dish, then pour over thickened sauce. Ready to serve with rice or noodles.