Although the name comes from the Arabic for ‘Indian dates’, tamarinds are not dates, but pods. They have a sour taste and are used extensively in Indian and Southeast Asian cooking. You find it in Oriental and Asian grocers, peeled and seeded in packets. Always bend and press the packets to make sure it is pliant; if it has gone hard then it has dried out and you will not be able to extract much pulp. To do so, break 450 g / 1 lb of it off in lumps, put these into a bowl and pour over 1 litre / 1¾ pints of boiling water, then leave to steep overnight. Strain through a sieve, working as much of the pulp through as you can with a wooden spoon. This extract is the tamarind water that is used in cooking, the leftover solids being discarded. Put the liquid pulp into ice-cube trays and freeze, transferring the cubes to a zip-lock bag so you will always have tamarind pulp to hand when you need it. You can now also buy liquid tamarind extract, which is simply thinned with hot water in a ratio of about 10 to 1.