We've always found something particularly satisfying about a recipe that minimizes waste by making good use of food scraps and leavings, whether that's a gambas al ajillo recipe that infuses the cooking oil with shrimp shells or crispy latkes that use starch from the shredded potatoes as a binder. Harnessing the natural properties of the bits and bobs that would otherwise be immediately discarded—the extra brininess hidden in the shrimp shells, the binding power of raw potato starch—can often get you better flavor or texture in whatever you're making, and you get to pat yourself on the back for being a thrifty cook. It's a win all around.
Another trick, though, can help you cut waste not just in your raw materials but in the steps taken to prepare them. It's an efficient way to combine some commonly paired ingredients and save a little bit of water in the process: When you're making a dish that calls for reconstituted dried mushrooms as well as wine or stock, soak the mushrooms in that wine or stock instead of in hot water.
The liquid will end up infused with the deeply earthy flavor of the mushrooms, and when you add it to the pot, all that flavor will go back in with it. It's a process akin to skinning charred peppers in a bowl of stock instead of under running water—another of our favorite shortcuts to flavorful liquid that can enhance a finished dish. Though you'll find plenty of recipes (here and elsewhere) that direct you to reconstitute the mushrooms in water, then add that tea-like infusion to the dish, swapping the water out for stock or wine that's already in the ingredient list means that your flavors won't end up diluted.
Here on Serious Eats, you'll most often see some version of this technique called for in recipes that incorporate dried porcini mushrooms—it's used in our smoky Penne Boscaiola, in savory Vegan Collard Greens (studded with bits of rehydrated dried mushrooms left over from making vegetable stock), in this 30-minute Pressure Cooker Mushroom Risotto, and in this day-after-Thanksgiving gravy made with porcini steeped in turkey stock. But it'll work with other dried mushrooms, too, including shiitakes and wood ears.
To hydrate the mushrooms for cooking, you'll need enough wine or stock to fully cover them. That's not a problem in most recipes, since dried mushrooms are rarely used in quantities of more than an ounce; if your recipe calls for a larger amount, you may want to stick with soaking them in hot water, or a combination of water and a more flavorful liquid.
You can heat the mushrooms and liquid together until steaming, in the microwave or on the stovetop, or heat the liquid separately and pour it over the mushrooms. Either way, they should steep for between five and 15 minutes, until they're thoroughly softened—and either way, your thrifty heart can rest easy in the knowledge that no flavor is going down the drain.