Deep mushroom is a reagent, not a recipe. If you wish to acquire more of this reagent, look around Kishibie village or haunted cave. There's lots to go around there.
there is no recipe for these you have to gather them, now there are transmute recipes to use them in but mostly just look around they are everywhere or when you feed things to your pet you'll get some also check the bazaar. But mostly just start gathering
thanks