In a 2 quart saucepan on medium heat, add the butter, onions and 5 spice powder. Saute for 3 minutes then add carrots, celery, celery root and parsnips. Saute for 10 minutes then add chicken stock. Reduce stock by 30 percent until the vegetables are soft but not mushy. Stir in the cornstarch slurry to thicken. Check for seasoning.