i used to farm the pearlfin monkeys and i got 4 of 5 recipes before the update its very tedious though , took hours its very RNG , i got my first in the 5 min , the other took around 2 hours total I think. Also the dailys that give " treasure of the vale " chests rewards , have a chance to give you the recipe , I used to did them too before the update till i learned they were bugged and werent giving anything ( yay .. )
Just check if they are working if they are , theyre the easiest way to get them , and try the monkeys , or the little basterds in kun lai cave.