Folded, liquid retaining, re-usable, glueless, leak resistant and heat resistant cooking vessels are described such as steaming pouches of the "papillote" type made from a flat sheet blank (1) by means of simple machining operations such as cutting, stamping and slitting, scoring and folding only, the vessels being storable as flat sheets (1) before use and between uses. The closed vessel ready for use in cooking can be folded by a user into a pouch which contains the food to be cooked or warmed which may include liquid. Embodiments of the invention can be used for cooking on a barbecue, in an oven or in a microwave oven and are easily cleaned even in a dishwasher as they can be flattened after use without rupture of surfaces or tearing.
