Abstract: The invention relates to a device (1) for steaming a product to be cooked, in particular food which is contained in an enclosed receptacle (18, 31) of a packaging unit (20), comprising a sealable cooking compartment (2), whereby the packaging unit (20) can be introduced into the cooking compartment (2) and be heated and wherein the device (1) comprises a perforation facility (10) for perforating at least, at least in sections, an outer covering (17) of the receptacle (18, 31) of a packaging unit (20) located in the cooking compartment (2). The invention further comprises a packaging unit (20) for such a device (1) as well as a system comprising such a device (1) and such a packaging unit (20).