Baking cakes is part of being Ponyville's Premiere Party Planner. It's a particularly important job when the cake is for frowny ponies, or the sort of folks who don't normally eat cake.

But it's something that Twilight Sparkle doesn't seem to understand. At least, if she understood, she probably wouldn't barge into Sugarcube Corner early in the morning, screaming about Changelings invading Equestria and covert smuggling rings and blah blah blah.

It wouldn't kill Twilight to show some decorum. She clearly needs to get her priorities in order.

EDIT: This is now the most likely candidate for the image source. Thanks to m2pt5 for the tip!