Yogurt is an ever-present feature in the food of the Eastern Mediterranean and North Africa, where - apart from being thinned to drink — it crops up all over the place in bread-making, sauces, relishes and soups. It is a fermented dairy product that is made naturally by airborne acid-producing bacteria but it is capable of being easily cultured. Around the Mediterranean, it is made most often from goats’ or sheep’s milk.
To make thick yogurt, drain it through a sieve lined with cheesecloth. Leave it long enough and what is in the sieve will thicken to a basic sour cheese, called labna in Arabic. It can be served dribbled with olive oil and with chopped mint as a dip in a mezze. How cheese-tasting the labna becomes and how thick it is will depend on how long you leave it to drain. It is fun to experiment with. Unsalted and while still of a spoonable consistency, it makes a simple dessert when dribbled with honey.
The trouble with using yogurt in cooking is that it separates the instant you put it into a hot liquid or bring it to the boil. It therefore needs to have a stabilizing agent cooked into it before it is added to a boiling or simmering liquid. The easiest way to do this is to add a level tablespoon of cornflour to every 575 ml/1 pt of yogurt, first mixing the cornflour to a paste with cold water. Put this with the yogurt in a mixer or processor and whizz briefly, or beat with a whisk until smooth and liquid. Season with a little salt, pour into a saucepan and bring to the boil over a low heat. Then simmer, stirring at regular intervals, for 10—15 minutes until thick and creamy. You can now pour it with impunity into your stew or dessert instead of cream. It is best used immediately and should not be covered, as this seems to have a destabilizing effect.