1 Place the noodles in a large heatproof bowl and cover with boiling water. Set aside for five minutes.

2 Flatten the lemon grass stalk with a rolli g pin or meat mallet and put in a pan with the stock and curry paste.

3 Finely chop the shallot, add to the pan and bring to the boil. Thinly slice the mushrooms, add to the pan and simmer gently for five minutes.

4 Stir the sugar, fish sauce and prawns into the soup and simmer for three minutes until the prawns are cooked. Thinly slice the chilli and salad onions.

5 Squeeze the lemon juice into the soup and season to taste. Drain the noodles and pile into two bowls. Ladle over the soup, scatter over the coriander, salad onion and chilli, and serve

Per serving: 107 Calories (kcal); 1g Total Fat; (7% calories from fat); 3g Protein; 27g Carbohydrate; 1mg Cholesterol; 7mg Sodium Food Exchanges: 1 Grain(Starch); 0 Lean Meat; 0 Vegetable; 0 Fruit; 0 Fat; 1/2 Other Carbohydrates