Coffee Yogurt is a Yogurt made for Miss Byng by Ollie. It is her childhood favorite, I think it was made by her dad.
Here's what you need to craft it. Sugar x1 Coffee Beans x1 Evaporated Milk x1
She had it while on a plane (maybe) in a childhood memory she told Ollie about.
She says "This is awful, you've ruined it". "Oh father why have you forsaken me".