Tea -> Reading Tea leaves-Tea - Azyr - Can't figure out why Azyr is fine with mushroom powder tea/instant mushroom soup. Oh well, their loss. It doesn't sound tasty.
Could be as complicated (and unnecessarily cruel) as Foie Gras, instead it's mushrooms forcefed on deer.
Could be as simple as roasting it in a kebab alongside other wild meats
Mushrooms in brine. Because iirc brine was also used in embalming.-??? - Shyish - My first thought was some kind of funerary food, but most of those tend to be deliberately plain flour stuff...fermentation should be okay with Shyish though. Fermented mushrooms sounds tricky, not enough sugar. Maybe soaked in wine?
Oven baked? Or ground through a mincer.