Marinate the beef in the soy sauce and sugar in a large bowl. Set aside.
In a food processor, blend together until very smooth all the paste ingredients and 100ml of the coconut milk
Heat a large saucepan over a medium heat until hot. Add the beef in one layer and cook for 3 minutes each side to brown well. Pour over the paste and the remaining coconut milk together with 250ml water. Bring this to a simmer, then reduce the heat to very low to simmer gently. Cook, covered for 3-4 hours until the beef is very tender.
Remove the lid and turn up the heat to moderate and reduce the sauce so that is very very thick and clings to the beef (about 15-20 more minutes). When the oil separates your work is done. Add salt if it needs any - sometimes it does, sometimes not.
As it's quite a dry curry, I prefer mine served with Malaysian style roti bread (buy the frozen ones - they're great), but it'll also work with jasmine rice.