If using dried shallots, boil 2 cups of water and pour it over. Let the dried shallots soak until soft. Drain and soak a couple more times and rinse it well. This will help get rid of the strong flavor, if there is any.
Add the finely chopped shallots to the yogurt, salt and mix well. Adjust as per taste. Transfer to a serving bowl.
Cover and let it chill until served. The flavors meld well when it is left to chill for some hours.
To serve, may drizzle some olive oil and sprinkle rose petals on the top.
Dried shallots and rose petals are available at Persian grocery stores or online.