Place all the net wrap ingredients in a mixing bowl. Add 500ml of warm water and whisk together until smooth. Allow to rest for 2–3 hours. Combine all the filling ingredients in a mixing bowl. Knead well, using your hands, and set aside.
Heat a non-stick wok or frying pan over a medium heat. Dip the fingers of one hand into the rested net wrap batter. Raise your hand out of the bowl, over a plate to catch any drips. Wait a few seconds for the batter to start running down in long dribbles, then drip the batter into the hot pan to form a round, lacy pancake. Allow to cook for a few seconds, then remove to a plate.
Repeat to make about 15 net wrap sheets. Lay a net wrap on a chopping board and scoop a heaped tablespoon of filling into the centre. Fold the left and right sides in towards the centre to enclose the filling, and then roll up from the edge closest to you, to form a neat, firm roll. Secure with a dab of egg white.
Repeat with the remaining net wrap sheets and filling, to make about 15 rolls.
Half fill a frying pan or wok with vegetable oil and heat over a medium heat, to 140°C (275°F).
Deep-fry the parcels in three batches, first placing them seam side down in the pan. Cook each batch for 6–8 minutes, or until crisp, turning them every 2 minutes.
Drain on paper towels, and then transfer to a serving platter. Serve hot, with a bowl of nuoc cham for dipping.
Note: Nuoc cham is a popular Vietnamese dipping sauce. To make your own, combine 1½ tablespoons of fish sauce, 1½ tablespoons of white vinegar, 1 tablespoon of sugar and 60ml of water in a saucepan over a medium heat. Stir well and cook until just before boiling point is reached, then allow to cool. Stir in 1 finely chopped garlic clove, ½ finely chopped bird’s-eye chilli and 1 tablespoon of lime juice and serve.