Can't speed up prep recipes

Does anyone else have this problem?
It's been weeks if not months since watching videos to speed up prep recipes has actually worked. 
I've been playing around the issue, being careful not to join group goals unless I already have what I need to complete it. 
But I screwed up today and wasted one of my boosts, and now I'm going to miss out on my 3 gold because I can't speed up recipes.
So. Frustrating!