Combine seasoning ingredients in a bowl except the tapioca flour. Add in prawns, meat and carrots. Stir well to mix. Add chopped spring onions and tapioca flour and mix thoroughly. Refrigerate mixture for 40 to 50 minutes.
Put 2 to 3 teaspoons of filling in the centre of each 'wantan' skin. Gather the edge of the wrapper to the top so that only the top of the filling is seen.
Line the bamboo steaming rack with banana leaf. Lightly brush with oil then place dumplings on it. Steam over rapid boiling water for 7 to 10 minutes or till cooked.
Serve dumplings with chilli sauce mixed with mustard.