I picked up the Colossus Fang Recipe from the Spider Queen, so it’s safe to say it just has to be dropped from a mini-boss.. not necessarily the end-boss.
I don’t think it matters which path you choose, but it seems pretty obvious to state that each recipe drop is specific to the dungeon you’re in.
i.e. don’t expect to find the Eternal Flame Recipe in AC.
:)
Ironbreakers General