A heat sealing jaw for use in cooperation with an opposing backing jaw for sealing layers of film together is described. The heat sealing jaw may be suitable for forming an easy-open feature on a packaging pouch used to contain flowable material. In certain embodiments the heat sealing jaw comprises a jaw body, a heat sealing element secured to the jaw body, a support surface for clamping the layers of film together against the opposing backing jaw, and, a heat sink coupled to the heat sealing element for inducing a temperature gradient along a sealing face of the heat sealing element. The sealing face may have a protrusion for forming a notch within the layers of film. Related apparatuses and methods are also described.