Before using fresh porcinis, remove the base of the stem and the vertical tubes under the cap. To reconstitute dried porcinis, soak them in hot water for 20 minutes. Save the soaking water for use in sauces and soup stock. Porcinis should always be thoroughly cooked, as they have a reputation for causing stomach upset when eaten raw. In addition, cooking brings out the flavor. Sauté or fry them for 5 to 7 minutes; or cook them in a small amount of liquid in a tightly sealed pan for 15 minutes. Once cooked, use them in any recipe that requires mushrooms. The flavor of porcinis blends especially well with Italian seasonings. Porcinis are also delicious when grilled. Brush the mushrooms with butter or oil just before placing them on the grill. Heat the mushrooms thoroughly, sprinkle them immediately with Parmesan cheese, and serve.