1. Boil the potatoes until fork-tender while preparing the filling. Heat the oil in a large skillet. Add the onions, garlic, carrots, peppers, and celery, and sauté until just tender. Add the mushrooms and tofu or meat, and stir gently, cooking until the mushrooms are lightly browned.
2. Sprinkle with the flour and stir for 1 minute. Add the broth, tomato paste, soy sauce, thyme, basil, and black pepper. Stir well and cook until hot, about 5 more minutes. Spoon into a casserole dish.
3. Preheat oven to 350º F. Drain potatoes. Mash with the butter or margarine, parsley, salt, pepper, milk, paprika, and grated cheese.
4. Spread the mashed potatoes over the top of the pie mixture. Make sure the potatoes cover the filling all the way to the edge. Set on a cookie sheet, and bake until lightly browned, about 40 to 45 minutes.