First make the dumplings. Combine the pork, prawns, spring onion, vinegar and cornflour in a bowl and season with salt and white pepper. Divide the mixture between the wonton wrappers then wet the edges with a little water, fold and twist to seal. Place on a tray lined with greaseproof paper and transfer to the fridge for 20 minutes until firm.
Meanwhile pour the chicken stock, chillies, ginger, garlic and mushrooms into a saucepan and bring to a simmer. Turn the heat down very low and cook gently for 10 to 15 minutes to infuse the stock. Add the dumplings, bring back to a simmer and cook for 3 to 4 minutes. Just before the dumplings are cooked, stir through the cornflour mixture and cook for a minute until thickened. Remove from the heat, stir through the spring onions and coriander and add lime juice and soy sauce to taste.