Palm sugar is the sweetener of choice for many southeast Asian cooks.
What is it? Sugar made from the sap of certain palm trees, including date and coconut palms. As with the sap from maple trees, palm sap is thin and watery when it's first harvested. The sap is cooked in large vats until it becomes thick and caramel like, and is then poured into moulds to harden. Palm sugar made in Thailand is paler and has a less smoky flavour than that produced in Malaysia and Indonesia.
How is it available? Usually in small cakes that retain the shape of the mould (such as small bowls or bamboo tubes). You can also sometimes find palm sugar in rough, uneven crystals.
What to look for? The cakes should be firm but not rock hard - when you break off pieces with a knife, they should be crumbly.
What else? Connoisseurs say each variety of palm tree produces a sugar with a different flavour. Some brands of palm sugar are mixed with cane sugar, which is cheaper because it's less labour intensive.
Store palm sugar in an airtight container because moisture can make it mouldy.