Cut squash in half lengthwise. Scoop out seeds and stringy portion. Place in a baking dish with 1/2 inch of water in bottom. Bake for about 1 hour at 350 degrees. While squash is baking, prepare the stuffing mix. Cook onions and mushrooms in 1/4 c. Water for 5 minutes. Add tamari and spices. Cook over low heat for 5 more minutes. Remove from het. Add the rice or the bread crumbs and mix together well. When the squash has baked about 1 hour and is almost tender, remove from oven. Fill each with stuffing mix. Return to oven and bake an additional 15 minutes.
May be served as is or with gravy. To prepare ahead, bake the squash for one hour and remove from oven. Let cool. Prepare stuffing. When ready to prepare dinner, fill with stuffing mix and bake at 350 degrees for 30 minutes.
