Cha gio (Vietnamese spring rolls)

To make the nuoc cham, place the fish sauce, chilli, garlic, water, lime juice, vinegar and sugar in a small bowl, and stir until the sugar dissolves.

Place the noodles and mushrooms in a medium heatproof bowl and cover with boiling water. Set aside for 10 minutes or until the noodles are tender. Drain. Use your hands to squeeze out excess liquid from the mushrooms. Remove the stems from the mushrooms and discard. Thinly slice the mushrooms.

Use clean kitchen scissors to cut the noodles into short lengths. Combine the noodles, mince, carrot, shallot, garlic, crab meat, fish sauce, sugar and pepper in a large bowl.

Soak 1 rice paper sheet in a dish of warm water until soft and pliable (don't soak the sheet for too long or it will tear). Transfer to a clean work surface. Place 1 heaped tablespoonful of the noodle mixture along the centre of the sheet. Fold in the sides and roll up tightly to enclose the filling. Place, seam-side down, on a baking tray and cover with a damp tea towel. Repeat with remaining rice paper sheets and noodle mixture.

Add enough oil to a large heavy-based saucepan to reach a depth of 10cm. Heat to 180°C over high heat (when the oil is ready a cube of bread will turn golden brown in 15 seconds). Add 5 spring rolls to the oil and cook for 2-3 minutes or until golden brown and cooked through. Use tongs to transfer to a plate lined with paper towel. Repeat, in 3 more batches, with the remaining spring rolls, reheating the oil between batches.

Cut each spring roll in half crossways, if desired. Serve with the nuoc cham, lettuce and mint leaves.