Kashk (sour yoghurt sauce)

Kashk is listed as an ingredient in several Persian dishes, so I made it a mission to work out how to make it. You could substitute whipped Greek yoghurt in these recipes, but I needed to find out what the difference was. 

First of all, you need sour yoghurt. I bought a tub of greek yoghurt from the co-op, weighing around 500g. I removed the protective foil and paper covering, and left it out on the side for a couple of days. 

The recipe itself seems completely mad to someone who has never made this before, but trust me, it seems to be legitimate. It involves adding water to yoghurt, boiling until dry and cooked, and then adding more water. 


  • 450g sour yoghurt
  • 450ml water (use this to rinse out the container)
  • A pinch of salt
  • More water to achieve consistency

It may be more cost-effective to make up a triple batch, and most recipes seem to start off with larger volumes. It is also available online from Persepolis in Peckham, if you want authenticity without the hassle. 


  • In a saucepan, mix the water and the sour yoghurt. Bring to a simmer, and then cook for over two hours. Stir every so often, more often towards the end. As the water evaporates, you’ll have an off-white, toasted mixture that is about the texture of choux pastry. Turn off the heat. 
  • Line a sieve with a cheesecloth, and put the mixture into the cloth. Wrap and squeeze the mixture, and then put a weight over the top to squeeze out any remaining water, which is discarded. This takes about half an hour. 
  • Take out the ball of the mixture, and put into a container until ready to use. This can be kept in the fridge for a week or so, or freezer until required. 
  • To make up a portion of kashk, put the mixture in a food processor with a good pinch of salt and around 60ml water, and leave to soak. Blend and add just enough water to make a smooth, soft creamy mixture, about the consistency of double cream. For Kashk Bademnjan, it should be slightly thicker. The mixture may feel slightly grainy. I’ve tried blending smaller volumes and it doesn’t really work. 


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