Kashk

Ingredients

• 2¼ lbyogurtfull-fat, preferably sour
• 2½ cupswaterfor thinning the yogurt
• ½ cupwaterfor blending the drained solids until creamy, to desired consistency
• 1 tspsaltadjust to taste; kashk should be slightly salty and sour

Method

1. Smooth out the yogurtIn a heavy pot, stir the yogurt together with the water for thinning until it is completely smooth and no lumps remain.
2. Boil until it curdlesBring the mixture to a boil over medium heat, stirring, until it separates and curdles.
3. Simmer low and slowLower the heat and let the yogurt simmer gently, uncovered, for about 1½ to 2½ hours. Stir every 10 to 15 minutes, until most of the liquid has evaporated and the mixture is thick and pale beige.
4. Thicken over higher heatRaise the heat and keep cooking for another 15 to 30 minutes, stirring constantly so the mixture thickens further. Scrape across the bottom of the pot as you go so nothing catches and burns.
5. Let it cool slightlyTake the pot off the heat and let the mixture cool a little.
6. Squeeze out the liquidSpoon the mixture into a nut milk bag or a clean cloth and squeeze out the remaining liquid firmly, or leave it to drain.
7. Blend until creamyPut the drained solids into a blender with the water for blending and the salt, and blend until creamy. Add the water gradually until you reach the consistency you like.
8. Taste, jar and storeTaste the kashk: it should be slightly salty and sour. Spoon it into a clean jar and keep it in the fridge for up to about 2 weeks, or in the freezer for longer.

Tips and variations

Traditionally, kashk is made with sour yogurt, ideally a local farmhouse yogurt; if yours is mild, leave it in the fridge for 2 to 3 days beforehand to sour. For a quicker version, boil the yogurt and water for just 5 to 10 minutes until it curdles, then hang it in a cloth bag to drain for 8 to 10 hours, and salt it only afterwards. Instead of the stovetop, you can also cook the mixture down in a shallow dish in the oven at 150 °C for about 2½ hours. In the old way, kashk is shaped into balls and dried in the open air and sun, or on a rack, turning them now and then; dried like this, it keeps in the cupboard. To serve, spoon the liquid kashk over Ash Reshteh or Kashk-e Bademjan and drizzle with mint warmed in hot oil. Garlic, ground walnuts, fresh herbs, saffron or a squeeze of lemon all suit it as well.