Methods of and device for retaining a moisture level of a food heated/reheated in a microwave oven are provided. The device includes a microwave splatter cover, a lid, or a lunch box integrated with a steam generator. The device is able to contain a steam generator capable of generating steam from added water when a microwave radiation is provided. The steam generator is able to rotatably couple with the center of the microwave cover. Water added to the cover is able to be temporary stored on the cover and subsequently flow to a dish structure underneath the cover. Alternatively, water is able to be added directly through a hole on the cover to the dish structure.