Doogh

Carbonated doogh is a popular soft-drink in Iran. This recipe was provided by Persiancity.com

Ingredients
 yogurt, one glass water, 2-3 glasses dried mint, one teaspoon dried pennyroyal, one teaspoon (optional) salt black pepper (optional) 

Preparation
Beat yogurt until it flows smoothly. Add mint, pennyroyal, salt, and black pepper, and mix well. Add water to yogurt gradually and mix as you add. The quantity of water can be adjusted to obtain the desired density. Place in the frig for a few hours. Mix again before drinking.