An apparatus and a method automatically cook food, for example, a hulled grain such as buckwheat, thereby conveniently providing the uniform and optimal cooking quality of the food to a user. The cooking apparatus includes a cooking cavity that contains food to be cooked and water therein, and a heating unit that heats the food and the water. The cooking apparatus further includes a control unit operated in such a way as to heat the food and the water at a preset initial output of the heating unit, first to reduce the output of the heating unit to a first reduced output and allow the heated high temperature water to be absorbed into the food after a first preset time has elapsed, and second, to reduce the output of the heating unit to a second reduced output and cook an inside of the food using the high temperature water absorbed into the food after the water has simmered.