Tofu is made by coagulating soya milk by Calcium sulfate (gypsum) or other coagulants. Because of its protein content it is a very popular ingredient in vegetarian and vegan dishes.
It is available as a fresh or pre-fried variant on Asian markets. The pre-fried one lasts longer in the fridge. You can freeze both kinds. It very easily overtakes flavour of other ingredients. It is used in soups, sauces, for frying and into sweet dishes too. Try Vietnamese fried tofu with lemon grass and chilies.
Recipes with tofu.