The cake at the end refers to a painting by Chagall that the main characters like in Notting Hill.
Spoiler alert, if you haven’t watched Notting Hill, you might want to stop reading this point. If you have seen it though, you might remember that at the end of the movie, during the wedding, we can see that the cake has a goat with a violin on it. This rather strange design comes from a painting by Marc Chagall titled The Bride. The actress mentions that “there is no complete happiness without a goat playing the violin” and we can see that, at the end of the film, they decided to have a cake with that goat as a reference to that line.