Where can I find 'RECIPE: L.5 Expert Leather Armor'?

[Gluttony]

Yes, you can buy it from CS. If not, then it drops in the Forest Haven campaign, I would say that Skeleton Crypts is your best bet but any of the maps will do.

Just make sure your character is around lvl 5 so you farm lvl 5 not 15. Most people do skeleton cult crypts cuz there's a few bosses there. Hope this helps.

Sorry Fuzzy, but it's a recipe and the level of the item is L1 so the level of the character doesn't actually matter. If it happens to drop as a L15 instead of a L5 it's merely coincidence.