Drain and slice tofu into rectangles (1/4" thick or less). Place in flat dish. Melt butter and mix with hot sauce until it tastes like buffalo sauce. Pour sauce over tofu, sprinkle with garlic powder, and allow to marinate at room temperature for 45 minutes to an hour.
In the meantime, slice onion and saute with mushrooms. Set onion and mushrooms aside.
After tofu has marinated, coat skillet with non-stick cooking spray and fry until brown or golden brown.
Place cooked tofu back in dish with buffalo sauce for extra flavor and coating.
Toast hoagie buns. Place tofu slices in hoagie buns (about 4 slices per hoagie) and then add the onion, mushrooms, and tomato. Drizzle remaining buffalo sauce over the hoagie. Add salt and pepper if desired.
This recipe is a simple and delicious variation on buffalo tofu. It allows for a lot of different veggies to be used; and if you use vegan margarine like, Earth Balance's Soy Garden, then it isn't nearly as bad for you as buffalo flavored items tend to be.