step 1 Cook the noodles following pack instructions. Refresh in cold water and drain well. step 2 Put the stock in a large saucepan and stir in the curry paste, lime leaves, fish sauce and 250ml cold water. Bring to a simmer and cook for 5 mins. step 3 Cut the fish into roughly 3cm cubes and add to the pan. Return to a simmer, then cook for 2 mins uncovered. step 4 Stir in the noodles, prawns and pak choi, and simmer for 2-3 mins or until the fish and prawns are just cooked. Serve in bowls scattered with coriander.