Combine pork, prawns, mushrooms and water chestnuts in a bowl. Add seasoning ingredients and stir with a pair of chopsticks until the mixture is well combined. Refrigerate for 30 minutes.
Take a piece of wantan skin and place a teaspoonful of filling in the centre. Fold into half and pinch the edges together, then gather the edges to form pleats. Leave the dumplings in the refrigerator for 20-30 minutes before boiling.
Prepare your own soup stock and drop in the prepared dumplings to cook.