Step 1

Break up the block of tamarind into about six pieces in a small saucepan and cover with 375ml ( 1 ½ cups) water. Bring to a rolling simmer over medium–high heat, stirring often for about 5 minutes. Then remove from the heat and let it cool for another 5 minutes.

Step 2

Using a wooden spoon or potato masher, smash the tamarind in the water. The sauce will become thick like ketchup. Run this through a sieve into a bowl, pushing against the solids as you do. You should end up with a thick tamarind paste. If you have ever used shop bought tamarind concentrate, this is what you have though shop bought tamarind concentrate is much more concentrated. Discard any solids that remain in the sieve.

Step 3

Return the tamarind paste to the saucepan and add the cumin, chaat masala (if using), ginger, chilli powder and sugar. Bring to a simmer for about 3 minutes until the sugar is completely dissolved. You can add a drop more water if you prefer a runnier sauce or reduce it more if you prefer a thicker sauce. Taste the sauce and add more sugar, salt or other spices to taste. (You will need to dissolve any additional sugar over a medium heat if added.)

Step 4

I store this in a convenient squirt bottle in the fridge.