PURPOSE: To prepare a heat-cooked food having high preservability and excellent taste and flavor by adding a seasoning liquid and/or ingredient to a heat-cooked food, stirring the mixture and aging the product after steaming.

CONSTITUTION: A seasoning liquid and/or ingredient are added to a heat-cooked food such as cooked rice or to a food under cooking. The mixture is stirred and steamed at 70-120°C for several minutes to effect the aging. As an alternative method, a seasoning liquid and/or ingredient are added to a food before heat-cooking, the mixture is stirred and heat-cooked and the product is steamed to effect the aging.