Mix all the sauce ingredients together in a jug ready for use.
Heat oil in a wok and add garlic and chilli and stir fry until fragrant (about 1 minute), then add the mud crab. Stir fry until the shells start to turn slight red and then stir in the sauce. Stir fry for a further 2 minutes and then cover with a lid and simmer for around 6 minutes or until the shells turn completely red.
Remove lid and stir in vinegar, add egg and stir to form shreds. Add coriander and spring onions, give it a stir and then serve immediately!!