The Iranian style soup would be the simplest explanation for Ash or Aash. Aash is very thick compared to soup. Since its thick and heavy, Its too heavy to be eaten as an appetizer, it’s a complete meal. There are many types throughout Iran, although some are popular all over Iran, like Halim.
Cooking aash has a somewhat troublesome procedure. Some ingredients such as the meat are cooked before hand, some are chopped or peeled and finally all ingredients have to cook in one pot and blend in. Depending on the amount of ash the cooking time varies. The common ingredients are grains, fresh herbs, spices. Ash has its own collection of fresh herbs.
Since it’s consumed on a daily basis in Iranian households, it is one of very few Iranian delicacies that can be bought from shops. There are specialized shops that are only dedicated to Aash, there is usually one in every neighborhood. The aash starts cooking from the night before and is ready very early in the morning, which is when you can purchase it. At about 7 in the morning its usually sold out (depending on the season the time varies).
This food is usually eaten alone, but some prefer to have it with bread. Some are mostly eaten as breakfast, these are the ones that can be purchased from the stores, such as aash sabzi, adasi, halim. Other types are homemade (its safe to say they cannot be purchased) and eaten as a whole meal.