Sweet and smoky red-cooked cod

• 500gr cod loin, cut into 2-3 inch chunks
• 1 tbsp shaoxing rice wine or dry sherry
• 3 tbsp rapeseed oil
• 2-3 tbsp potato flour (or plain flour)

For the sauce:

• 2.5cm piece fresh ginger, sliced into rounds
• 1 cinnamon stick
• 1 star anise
• 1 tsp sichuan peppercorns
• 3 tbsp premium reduced-sodium light soy sauce
• 2 tsp premium dark soy sauce
• 1 tbsp chinkiang black rice vinegar or balsamic vinegar
• 3 tbsp soft brown sugar