Mix the laos, turmeric, lemongrass, shallots, lime zest, star anise and garlic in a mortar or food processor to make a curry paste. Chop the chilli very finely to a paste.
Bring half the coconut milk to the boil and cook until almost solid.
Add the curry paste and cook until the aroma is released. Add the chilli, soy sauce and trassi.
Mix well and add the soy chucks and potatoes.
Add the other half of the coconut milk and cook for about 5 minutes.
Add the sugar, curry, onion, beans and salt and simmer gently for another 15 minutes
