Pour the boiling water over the dried porcini mushrooms in a small bowl. Let them sit and re-hydrate for 15 minutes and then lift the mushrooms out of the liquid with a slotted spoon. Coarsely chop the mushrooms and set them aside. Strain the soaking liquid (now mushroom stock through a fine strainer and set this aside as well.
Add the sherry and simmer for another minute. Add the chicken stock, mushroom stock, chopped re-hydrated porcini mushrooms, wild rice and sprigs of thyme. Cover and lock the lid in place.
NOTE: If you store the soup for another meal, it will continue to thicken. Loosen the soup as desired with more chicken stock or water before re-heating and serving.