• 4 blue swimmer crabs (about 400 g/14 oz each) (or 2 live mud crabs, about 800 g (1 lb 12 oz) each)
• 4 cloves garlic, thinly sliced
• 2 cm (¾ inch) piece ginger, thinly sliced
• 1 teaspoon salt, plus extra to taste
• 1 tablespoon vegetable oil
• 1 red onion*, thinly sliced
• 1–2 thin green chillies*, halved lengthways (optional)
• 3 vine-ripened tomatoes, diced
• 1 teaspoon fennel seeds
• 1 teaspoon fenugreek seeds
• 2 teaspoons dried chilli pieces*
• 1 teaspoon unroasted chilli powder*
• 375 ml (13 fl oz/1½ cups) coconut milk*
• 3 sprigs curry leaves, leaves picked
• juice of ½ lime

If using live mud crabs, place them in the freezer for 1-2 hours until they are completely immobilised before you begin chopping them.

Remove the triangular flap under the crab and discard it, then lift off and remove the head, keeping the head to cook with the rest of the crab for presentation. Remove the gills and any yellow ‘mustard’. Wash the crabs. Cut in half, then pull off the big claws. Using the back of a large knife, tap the claws to crack them; this allows the flavours to seep in while cooking. Wash the crab pieces and set aside.

Using a mortar and pestle, pound the garlic, ginger and salt into a paste. Heat the oil in a large wok or heavy-based saucepan and cook the onion over medium heat for 3 minutes. Add the chillies and the garlic and ginger paste and cook for 1 minute. Stir in the tomatoes, fennel seeds, fenugreek seeds, dried chilli pieces and chilli powder; cook for 1 minute. Add the coconut milk, curry leaves and crab pieces; simmer for a further 10 minutes, or until the sauce has thickened and almost completely reduced, making sure to turn the crab regularly. Remove from the heat, add the lime juice and season to taste with salt.