Step 1

Stir fish sauce, sugar, juice of 1 1/2 limes, 1 tablespoon coriander and half the chilli in a bowl until sugar dissolves. Set aside.

Step 2

Toss crab with remaining lime, chilli and coriander. Season. Fill a dish with warm water, then dip 1 rice paper in water for 30 seconds. Remove and pat dry with a towel.

Step 3

Lay paper on a bench and place 2 tablespoons crab at end nearest you. Top with some carrot, avocado, onion and cress. Fold in sides of paper, then roll up to enclose. Repeat to make 8 rolls.

Step 4

Halve and serve with sauce.