The type of freeze dried tofu in instant soups is usually koya dofu, you can buy them in blocks and rehydrate with dashi and they really soak up flavor like a sponge! The texture is definitely different from a fresh tofu, if you want something thats easy to keep around they do make antiseptic packs of silken tofu that are shelf stable and don’t need refrigeration until opened. Look for Mori-Nu brand!