Originally I wasn’t planning on giving this cover any serious thought. However, a friend of mine came up with a way of looking at this that turned out to be surprisingly fruitful. The “real” cover for volume 11 is focused on Marquis Machina, whose picture frame contents are Noé. If one were to assume that this represented some form of meddling from the person outside the picture frame, then it’s not that hard to get what’s happening in this one.
The cover shows Vanitas at the end of the Amusement Park arc: dressed in unfamiliar fashion after his deathmatch with Noé just about murdered his clothes, and wielding in his hands Noé’s very favorite thing, one delicious looking apple pastry. The sparkles can also represent not just the tarte tatin’s wonderfulness, but stars. This is a pretty old and still mostly unexplained symbol of Noé and Vanitas.
Like how Noé is the object of the machinations of Francis, Vanitas had machinations of his own through his apology to Noé. Vanitas is generally manipulative, but a rather kind and ordinary version of this tendency manifests itself in him trying to do what he knows best would make Noé happy. Judging by the reaction, it worked quite well.
The cameo of Murr is pretty cute, too.