Begin by making the crust. Stir the yeast into the warm water and let sit for a few minutes. Add the sweetener, mix well and let sit for a few minutes. Add half the flour and all the remaining ingredients except the oil and extra flour, and mix thoroughly with a fork. Slowly add the remaining flour and use your hands to mix once the mixture gets too stiff. Knead the dough for 10 minutes. Put the oil in a 3 quart bowl and spread it around. Place the dough in the bowl and press it into the oil, turning it over and covering the other side as well. Cover the bowl with wet paper towels or cloth and put somewhere warm for 1 hour. While the crust is rising, steam the spinach until tender and chop up the other vegetables. In a large skillet, heat the oil. When it is hot, saute the green onions, green pepper and mushrooms until tender. Add the seasonings, along with the crumbled tofu during the last half of the saute. When the dough is ready, preheat the oven to 425 degrees. Knead down the dough a minute or so and divide into 4 parts. Knead each part 2 minutes and form into a ball. Roll out each ball into a circle using extra flour if needed to keep it from sticking, and turning the circle upside down occasionally. Add the spinach and the soy cheese to the vegetable tofu mixture and put 1 quarter of the mixture on half the circle. Fold the circle in half. Turn up and press the edges together with a fork, all around, to create a half moon turnover. Repeat the process with the other 3 calzones and place them in a lightly oiled flat baking sheet. Bake 25 minutes until nicely browned and firm. Smother with tomato sauce and enjoy with a salad.