Method

1. For the Nuoc Mam Cham fish sauce, combine the fish sauce, rice vinegar, sugar and ½ cup of water in a saucepan and place over medium heat. Stir well and cook until just before boiling point is reached, then remove from the heat and allow to cool. To serve, add the garlic and chilli, then stir in the lime juice.

2. Put the mushrooms in a bowl, cover with water and soak for 20 minutes, then drain and thinly slice. Soak the bean thread vermicelli in water for 20 minutes, then drain and cut into 4cm lengths. Meanwhile, pound the prawns to a paste using a mortar and pestle.

3. In a large mixing bowl, combine the mushrooms, vermicelli, prawn meat, pork, crabmeat, onion, sugar, sea salt, white pepper and fish sauce. Knead the mixture in the bowl for about 3-4 minutes until well combined.

4. Working with one rice paper at a time, submerge the rice paper in a large pan of warm water, then transfer it to a chopping board or work surface. Take 1 1/2 heaped tablespoons of the mixture and place it on the bottom edge of the rice paper. Fold the two adjacent sides, one on top of the other, into the centre. Roll the apex to form a nice firm roll, and secure with a dab of egg white. Repeat until you have filled all the rice papers.

5. Pour the oil into a wok and heat to 180°C. Fry the parcels in batches for 6 minutes, or until lightly browned and crisp. Serve with the fresh herbs and lettuce and dip into the nuoc mam cham.