Here's a little tip with firm tofu that can cut cooking time by more than 50%. The problem with tofu is that it doesn't really last long even in the fridge. You can remedy that by pre-frying and freezing the tofu. If you cook a lot of tofu dishes at home, fry the tofu in bulk. Cut three or four tofu cakes into desired pieces, deep fry in vegetable oil, drain on paper towels, cool then store in freezer containers. Divide the fried tofu so that the content of each container is good for one complete dish. When you're ready to cook them, take out a container and thaw the tofu completely before tossing into the hot sauce. Allow to simmer in the sauce until heated through...