Prepping. In most instances, you’re going to want to rehydrate dried mushrooms. While boiling water is a common tactic, Bone says you can rehydrate in any liquid you want, including those called for in a recipe (milk, cream, broth, etc.). Generally you want it to be hot, though she teases a recipe from one contributor to “Fantastic Fungi” in which cream and dried porcini are combined in a jar and placed in the oven on the lowest setting, getting you perfectly hydrated mushrooms and thickened, mushroom-infused cream. “You just want to spread that stuff all over your body,” Bone says.