For soymilk custard, whisk soymilk, egg and soy sauce in a bowl to combine. Divide into 2 heatproof 18cm-diameter bowls. Cover with plastic wrap and steam in a bamboo steamer over a saucepan of boiling water until custard is set and firm but still a little soft to the touch (15-18 minutes). Keep warm.
Combine ginger, chilli and garlic in a bowl. Combine chilli bean paste, soy sauce, oyster sauce and sugar in a separate bowl. Heat a wok over high heat until smoking hot, add oil, then pork and cook, stirring constantly and breaking up pork with spoon. When pork is cooked three-quarters of the way through (2-3 minutes), add ginger mixture and cook for 30 seconds. Add chilli bean paste mixture and cook for 30 seconds. Add chicken stock and cook until sauce is reduced and meat is coated (3-5 minutes). Remove from heat, add Shaoxing wine and chilli oil. Divide among cooked custards and top with Sichuan pepper, spring onion and coriander. Serve with steamed rice.
Note White soy sauce, also known as shiro shoyu, is available from Japanese grocers such as Tokyo Mart and Chef's Armoury.