In a pot of boiling, well salted water, blanch shiso and spinach for 30 seconds and shock in ice bath. Squeeze out water and place in blender cup with salt and sugar. With blender on high speed, add canola oil in a steady stream. Blend for 5 minutes until cup gets slightly warm. This oil may be done a day in advance and will keep in the refrigerator for at least 1 week.
Recipe Courtesy of Ming Tsai