Tahdig is a speciality of Persian cuisine and Mesopotamian cuisine consisting of crisp rice taken from the bottom of the pot in which the rice is cooked. The name comes from a Persian word meaning "bottom of the pot". It is traditionally served to guests at a meal. Ingredients commonly added to tahdig include yogurt and saffron, bread, potato and tomato. Variations on 'Tahdig' include placing thin vegetable slices at the bottom of the pot, so they crisp up instead of the rice. Common vegetables include potato and carrots. Iranians also apply this 'crisping' method to spaghetti as well, providing a crisp spaghetti base.
Iraqi rice cooking is similar to the method used for Persian chelow, a multistepped process intended to produce just-tender, fluffy grains of rice. A prominent aspect of Iraqi rice cooking is the hkaka, a crisp bottom crust. It differs slightly from the Persian tahdig, which is a single thick piece; the hkaka contains some loose rice as well. Before serving, the hkaka is broken into pieces so that everyone is provided with some along with the fluffy rice.