Abstract: The present invention comprises an improved extruder die assembly and method for using same to impart a distinct colored and/or flavored pattern into an extrudable food mass during the extrusion process while improving the quality of dimensional design aspects of the resulting extruded, complexly shaped, direct expanded food products. The improved system includes an improved extruder die assembly comprising a converging nozzle section having axially aligned ridgelines which gradually project into the bore of the nozzle as the nozzle converges to gradually disrupt the axial flow of an extrudate at specific peripheral points thereby altering the extrudate's velocity profile. By gradually disrupting the axial flow the extrudate in close proximity to the projecting ridgelines in the converging nozzle prior to its extrusion, the dimensional quality of the resulting direct expanded food piece is greatly improved.