Kinda old trick, but still valid and doesn't take much effort. When you turn in Scourgestones, you get a Argent Dawn Valor token. 20 minion stones, 10 Invaders, and 1 corrupter's will give you a token each.
In instances you can tell everyone that you "need" the recipe, if its BOE, and when they say you have to learn it right there, just use your valor token and it gives the same emote as learning a new skill.
Kinda scammy/kinda exploity. But its worked in the past quite a bit.