Where does the plan for Griswold's Perfection drop?

I found multiple ingredients for this item:

Now I would like to know where the plans can drop. Is there a specified boss / location for this or is it just random anywhere as most of the stuff in the game? Plans do tend to drop from specific bosses though.

4 Answers

All Legendary equipment recipes are random, but the locations of materials can be found here.

I found mine on Manglemaw at Torment V (70).

I got mine in a cache after completing bounties. Like every other legendary crafting pattern, it's 100% random (except for Reaper's Wraps). Good luck!

Its random, I got mine from a rift boss in act 1.

It looks like Act 1, Cathedral lvl 2, in the bookshelf is the place to look.