The crisp Persian rice layer formed at the bottom of the cooking pot is called tahdig.
Tahdig literally means “bottom of the pot” in Persian. It is the browned, crisp layer that develops when rice cooks beneath a layer of steam and fat. The rice is commonly prepared in a covered pot, with oil or butter helping the bottom layer turn golden without burning.
Although plain rice can produce tahdig, cooks also make versions using slices of potato, flatbread, or even lettuce beneath the rice. These additions create a separate crisp layer while protecting the grains from excessive heat. The finished tahdig is often loosened from the pot and served as a prized part of the meal.
Tahdig is not itself a stew, rice variety, or bread. It is a cooking result and can accompany many Persian rice dishes, including chelow and polo. Its color and texture depend on heat, fat, cookware, and cooking time, so cooks often treat achieving an intact crust as a mark of skill.