Soak dried Porcini or Shiitake mushroom in a bowl of warm water for about 20 min (can boil the mushrooms if fresh). The mushrooms then can be used as an ingredient to a variety of recipes but more importantly, the bowl of water is now an umami bomb, and can be used as a broth or seasoning to add a ton of flavor to a bunch of dishes (pasta sauce, soup, stir-fry...)
Porcini in particular has an earthly, nutty taste and can be used to create complex sauces with a "beefy" taste.
FTFY