1. Turn each crab upside down. Pull off the top shell from the first, discard the grey gills and wash in cold water. Pull off the claws, chop the body in half and crack the hard shell on the claws with the back of a cleaver. Repeat with remaining crabs.

2. Soak the noodles in warm water for 5 minutes. Drain well.

3. To make the spice paste, pan-roast the chillies for a few minutes until blackened, then remove any stem and grind to a powder. Pan-roast the peppercorns and coriander seeds until fragrant and then crush in a mortar with a pestle. Add the chilli and other paste ingredients, and pound everything together until you have a coarse paste.

4. Put the stock ingredients into a small pot, bring to the boil and boil for 1 minute, then add the spice paste and cook for another minute.

5. Place noodles and crabs in a wok, pour over the spiced broth, bring to the boil and cover. Cook over medium heat for 8 minutes or until the crabs are cooked.

6. To serve, arrange the crabs and noodles in a wide, shallow bowl and top with the coriander and shallot.