Method and apparatus for heating and / or food is steaming

The invention relates to a process for cooking and / or heating food comprising a steam supply steam expansion chamber (3) comprising a containment wall (4) which is deformable and / or movable partially defining an enclosure (2) receiving food to be heated and / or cooked. The invention also relates to an apparatus for cooking and / or heating food, comprising a steam generating device (1) and an enclosure (2) for receiving food to be heated and / or cooked. According to the invention, the apparatus comprises a steam expansion chamber (3) supplied with steam by the steam generating device (1), and steam expansion chamber (3) comprises a containment wall ( 4) which is deformable and / or movable partially delimiting the chamber (2).