Soak dried mushrooms in water until soft, trim of the stalks. Bring a pot of water to boil , blanch pork trotter for 15 mins, Wash & drain. Rub the skin with 2 tbsp of dark soya sauce, set aside.
Heat 2 tbsp oil in Instant Pot using the Saute function. Saute B until fragrant, add in C , put in A.
Secure the lid and select Meat/Stew on More. Natural Release pressure when done cooking.
Open the lid and thicken the sauce with 1 tbsp cornflour mixed with 2 tbsp water. Bring to a boil until thick. Add in chestnuts.