The invention provides a cooking utensil for cooking food under pressure including a vessel, a lid, and a bayonet-fitting locking system, said utensil including a lid subassembly that includes both said lid and a support attached to said lid in such a manner that said lid can pivot, said utensil including a control member for controlling the locking / unlocking, and a transformation device for transforming the movement of the control member into pivoting of the lid relative to the support, said control member being shaped to be capable of being taken hold of manually and being connected mechanically to the support so that said lid subassembly being lifted manually, via the control member, causes the control member to be urged back into its unlocking position.