Porcini mushrooms have two lives. They enter this world first—and fleetingly—as sizable, fleshy fungi with spongy caps and thick, meaty stems, looking rather like heavily padded umbrellas.

Extremely perishable, porcini that aren’t sold fresh are often dried. In this second incarnation, they don’t look as impressive—they’re shriveled slices of their former selves. But don’t be fooled: even in this state, they have a rich, woodsy aroma that signals their concentrated flavor and rich culinary potential. While fresh porcini make for delicately earthy, luxurious eating, reconstituted dried porcini have a deeper, smokier personality and a chewier texture, and they’re used as a flavoring rather than as a vegetable.

Picking porcini by sight

Dried porcini are much easier to find than fresh. You can buy them at many supermarkets, in gourmet groceries, and by online (tryD’artagnanorBoscovivo USA). They’re pricey (about $5 per 1/2-ounce) but, like other potent flavorings, a little goes a long way.

Quality can vary.Because porcini are most often sold in cellophane, you have to judge them by their looks. If you can smell them, check that they smell woodsy and earthy, not musty or medicinal. Be sure the label says porcini (orcèpes, their French name, or the Latin牛肝菌属菌类可食的). Generically named “dried mushrooms” will be just that: an unnamed variety (or varieties) that’s pallid in flavor compared to real porcini.

In general, darker color means more intense flavor.I look for large, intact, beige pieces; their more delicate flavor is more to my taste. Extremely dark porcini may be older and unpleasantly strong. Whether light or dark, a uniform color is a good sign.

Look for a lot of caps.I like to see more arc-shaped cap pieces than rectangular stems. The stems are equally flavorful, but their ends can be tough and encrusted with dirt, requiring a quick trim (which is easier to do after they’ve been rehydrated). Finally, the best porcini should be free of the rough texture and pinholes made by insects. Store dried porcini in a cool, dry place in a closed container.

Experiment with dried porcini

• Sauté chopped garlic, parsley, fresh sage, and lemon zest together in olive oil with coarsely chopped rehydrated porcini and spoon over chicken, veal, pork, or fish fillets.

• Sauté rehydrated porcini with other mushrooms and serve on grilled bread under a blanket of melted fontina or mozzarella.

• Stir rehydrated porcini into soft polenta with finely diced, cooked onions, carrots, and fennel or spoon the mixture on top of sautéed polenta squares with shavings of parmigiano reggiano.

• Top grilled fish with porcini oil and diced tomatoes and serve garnished with fresh basil.

• Cook sliced or diced potatoes in porcini soaking water (extended with more water as necessary), toss with porcini oil, crumbled goat cheese, and fresh chives.

Use the “liquid gold” you get from soaking

Dried porcini are most often rehydrated before use. I use about a cup of warm water per ounce of porcini and let them soak until tender, usually about 30 minutes. The dark-brown liquid that results has more flavor than the porcini themselves. Strain it through moistened cheesecloth or just pour it off carefully, discarding the sediment in the bowl. Use this potent porcini “liquor” to enrich a vegetable broth or soup, a stew or risotto, or as the basis of a sauce. But be careful: too much of this liquid can overwhelm your dish. (You can dilute its flavor by starting with more soaking water.)

Give the rehydrated porcini a final rinse in clean water to get rid of any stubborn grit. After rinsing, I drain the porcini on a double layer of paper towels, cover with another sheet, and pat them dry.

I love to add porcini, first sautéed in olive oil or butter and seasoned with salt and pepper, to a simmering tomato sauce. They contribute great texture as well as a subtle flavor. I usually add some of the soaking liquid as well.

Try porcini oil and “dust”

Porcini oil is a wonderful condiment that can turn a simple piece of fish or chicken into a gourmet dinner. Simply simmer rehydrated porcini in olive oil and a little salt for about 15-minutes to lightly infuse the oil; purée the mixture in a blender or a food processor, and store it in the fridge. Its flavor will build over the course of a few days and it will last at least a month. You can use the oil only or mix the solids and the oil together for a fuller flavor. Then spoon the redolent, woodsy oil over cooked fish or meat.

Make porcini powder by whirring dried (not rehydrated) porcini in a food processor or blender. Mix a little of this “dust” into a biscuit.