Thermoplastic vulcanizates having improved physical properties, including extrusion surface roughness can be achieved by a method that includes a first processing step to form a fully cured TPV base, a cooling step wherein the fully cured TPV base is solidified and a second processing step which imparts improved physical properties including improved extrusion surface roughness to the resultant TPV. The method may be adapted for use in conjunction with a peroxide curing agents to protect a portion of the thermoplastic, which may be polypropylene, from degradation by the peroxide curing agent. The adaptation to the methods may include the addition of a portion of the thermoplastic to the TPV after the peroxide curing agent has been added. The adaptation may also include one or more devolatalization steps with or without the addition of a stripping agent.