- [Sheri] Next time on "The Key Ingredient." Mushrooms have been around forever, but these tasty fungi are having a moment. I'm going to show you a simple but impressive mushroom soup, and then classic buttery mushrooms on crunchy grilled bread. We head into the woods and then to the kitchen where my friend John Fleer and I use them in an Appalachian inspired recipe you're gonna love. [soft music]