This is a natural sweetener - an unrefined yellowy-brown coloured sugar made from boiled sugar cane juice and is sold in large lumps and found in Indian and Thai stores.

It should be sticky and easy to crumble rather than rock hard and is popular in India as a sweetener for its caramel-treacle like flavour. It is also used in Indian cooking to add a sweet-sour taste to vegetable dishes and for desserts, pickles and some curries.

If you can't find it, use demerara or light muscovado instead, though both lack the unique taste of jaggery.