Saute snow peas, mushrooms, onoins, and water chestnuts in sesame oil. Stir in bean sprouts. Mix tamari into tofu and blend well. Add it and 1/4 pound mashed tofu, flour, nutritional yeast and baking powder. Mix well and form into patties 4 inches in diameter. Oil baking sheet with olive oil and bake in preheated 325 F oven 30 minutes. Flip patties over and bake another 15 minutes. Serve with Mushroom Gravy. MUSHROOM GRAVY: (Soak 5 or 6 shiitake mushroom caps in water beforehand.) Combine water in which mushrooms have been soaked and remaining ingredients and cook on low heat until thickened. "The Associated Press"