I brought this from my hometown in Hubei. What is this? How to eat

Black taro, also known as water chestnut, is a shallow perennial herb of water chestnut in Cyperaceae, which is eaten together with bulbs as a vegetable. In ancient times, it was called fumi (fumi), commonly known as horseshoe, also known as chestnut, which was named after its shape like horseshoe and chestnut. Calling it a horseshoe only refers to its appearance; It is like a chestnut, not only in shape, but also in taste, composition and function. Because it bears fruit in the mud, it is called a chestnut. The skin of water chestnut is purple-black, and the meat is white. It tastes sweet and juicy, crisp and delicious. Since ancient times, it has the reputation of underground Sydney, and northerners regard it as Jiangnan ginseng. Water chestnut can be regarded as fruits and vegetables, and it is a popular seasonal product.