Recipe from Lebanese Cuisine by Madelain Farah
1 egg (or 1 tablespoon cornstarch dissolved into 1/2 cup cold water)
1 1/3 cup water
2 teaspoons salt
In a pan, beat egg well with a fork (if using cornstarch, first dissolve in 1/2 cup of cold water before blending with yogurt). Add the yogurt and water, blending thoroughly for at least 5 minutes.
Place on medium fire and stir constantly with a wooden spoon in one direction for 20 minutes or until sauce comes to a boil. Add salt and continue cooking for a few more minutes.