Doogh is the salty, fizzy yogurt drink served in tall glasses with lunch across Iran, and above all with kebab and rice at the chelow-kababi restaurants of Tehran. Bottled sparkling doogh from the mineral springs of Abali, in the mountains east of the capital, is the famous one; at home it is mixed from yogurt, cold water and soda water with crumbled dried mint, and sometimes wild pennyroyal (kakuti) or rose petals. Its bubbles and mint set it apart from plainer, still yogurt drinks. It is cooling and good with rich, herby food. Chef's tip: add the sparkling water last and stir gently, or the fizz disappears before it reaches the glass.