Break up the tamarind and dates and put them in a pan with the jaggery and enough water to cover them, about 500ml. Bring to a simmer and cook for 20 mins or until the tamarind is really soft.

Remove the pan from the heat and push the pulp through a sieve to remove any fibres. The sauce should be a coating consistency – add a little water if it is too thick.

Stir in the ginger powder, garam masala and ground cumin. The sauce should taste sweet and tart – stir in a little more jaggery if it doesn’t taste sweet enough. Chill before serving. Will keep in the fridge for three to four days.