You can swap the crabmeat (blue swimmer, spanner or mud crab) for cooked prawns or leftover roast chicken, or serve this som tum as a vegetable side dish. For vegetarians, substitute crab with silken tofu and fish sauce with soy.

Use a lemon zester to scrape the carrot and green papaya into ''noodles'', or shave with a vegetable peeler then cut into matchstick-thin lengths. Shave the cucumber lengthways.

Mix the rice vinegar and castor sugar in a bowl, and add the cucumber, carrot and green papaya, tossing well. Set aside for 30 minutes. Pound the chilli, garlic and sugar in a mortar with a pestle. Add the cherry tomatoes and bruise lightly.

Stir in the tamarind, lime juice and fish sauce. To serve, drain the cucumber, carrot and green papaya, and toss in the cherry tomato dressing. Add the crab meat, coriander and basil leaves and toss lightly. Scatter with crisp-fried shallots and serve.