Provided is a sealing gasket for a cooking utensil for cooking food under pressure, the utensil includes a vessel and a lid that define a cooking enclosure. The gasket having a heel from which at least a first lip projects that is provided with at least one escape window notch that passes through its thickness, and in that the first lip forms a differential movement member enabling the escape window notch to effect a relative movement relative to the heel when the pressure prevailing inside the cooking enclosure exceeds a predetermined threshold, which relative movement enables said escape window notch to open up a leakage orifice via which the cooking enclosure is put into communication with the outside of the utensil. Cooking utensils for cooking food under pressure such as a pressure cooker are provided.