Up until Twilight deduced everything at the end, I was genuinely convinced it was Pinkie who ate everything. I'd figured she had eaten the Cakes' cake due to a sheer lack of self-control, and that would explain her accusing everybody else and how she reacted to Twilight mentioning she was near the cake all night. The only thing missing was that she wasn't a butler. 'Course, I also expected an immediate scene cut after she said she'd stay up all night to her sleeping by the cake, so this episode subverted a lot of my expectations. Incidentally, I also though that the exact same thing about the Mare-Do-Well (her being Pinkie, not the scene cut), too, and
they both turned out pretty much the same way in the end.
*Twilight Zone theme plays*