Place 2 tbsp teriyaki sauce and the Walnuts in a small frying pan and fry for 1-2 minutes until just beginning to caramelised, set aside.
Meanwhile, cook the noodles in boiling water for 5 minutes, drain and run under cold water.
Mix the stock cubes with 1 litre boiling water in a large saucepan and add the carrot, green beans and prawns, cook for 3 minutes, add the cabbage and cook for 1 minute more then stir in the remaining teriyaki sauce.
Divide the noodles between 4 bowls, spoon over the stock, vegetables and prawns. Sprinkle over the teriyaki Walnuts to serve.
Cooks tip
Serve the noodle soup topped with cooked tempura prawns for an extra special occasion.