Cook noodles in a large saucepan of boiling water until tender and then drain. Rinse under cold water.
Heat oil in a large saucepan over medium heat. Add the garlic, lemon grass and ginger and gently cook until fragrant. Add the curry paste and cook 30 seconds. Add the stock, soy sauce and sugar and bring to a boil. Reduce the heat and simmer 20 minutes.
Stir in coconut milk, prawns, mushrooms, spinach, lime juice, and coriander. Cook for 5 minutes or until prawns just change colour.
To serve, place rice noodles into serving bowls and ladle over soup. Garnish each bowl with spring onion.
My husband and I really enjoyed this soup. He loves prawns and I love chicken so at the end I split it and mad ehis with Prawns and mine with chicken so we were both happy. I would add more red curry paste next time though because it was not as hot as I was expecting - 15 Jun 2009
Love laksa but never made it at home before. This was easy and delicoous. Tried chicken, shredded cabbage and sliced capsicum, also sliced beef, eggplant and basil - always great. Used less paste to cater for a noodle-loving toddler. - 21 Jan 2012