Tempeh is a fermented whole soybean product originally from Indonesia. It is full of proteins, fiber and vitamins, so it is very popular among vegetarians and vegans.
It has a better nutritional profile than tofu, as the soybeans are used whole and the production process is different. In Indonesian cuisine it is usually fried first and than mixed with sambal, sauces or put into curries or other dishes. Tempeh you can get in Indonesia you can use as it is. If you get imported, drier one, it needs to get soaked in salt water for a few minutes before cooking. Traditional way of packaging in Indonesia is in a piece of a banana leaf.