The tamarind tree produces brown pod-like fruit whose seeds and pulp are used to make tamarind paste. It’s deliciously sour, tangy and sweet and gives a great balance to a few dishes in this book. Typically, I buy it in block form, which is now easily available, then take off a golf ball sized piece (which is around 45-50g) and place it in a small bowl, cover with boiling water and leave it to break down and loosen over 15 minutes. Break it down further with a spoon or, as the water cools, with your hand. Then it is simply a case of straining it, using a spoon to push all the paste through the sieve. You then discard any stones or fibres left in the strainer and use both the tamarind paste and liquid in the recipe. You can use tamarind concentrate paste, but this is a lot stronger and ranges from brand to brand, hence I have said to use between 1 and 2 teaspoons as an equivalent. My advice would be to use a teaspoon, then after a little cooking to taste test and decide whether it requires an extra teaspoon to give more sour notes. Both block form and concentrate paste should be stored in the fridge once opened.