If all you do is toss these into stir-fries, then you have no idea how good shiitakes can taste. In Asia, they are nearly always sold dried, because drying them intensifies their deep umami flavor. With that in mind, sauté fresh shiitakes, but cook them longer over medium heat, until their moisture evaporates and the flavor concentrates. Or try this: Stem and slice fresh shiitakes into ¼-inch pieces, season with salt, and coat with oil. Lay them on a sheet pan and roast at 350° for 15–30 minutes, stirring occasionally, until brown, dry, and crisp.