How do you suppose plums would work for a cobbler? You could add the lemon zest and nutmeg (which absolutely made the plum cake) to the plums directly but then finish with a more crispy topping.
Having said that, I am really enjoying the soft and slightly almond/lemony cake-y-ness of my plum cake right now (it was better the next day. And yes, I will admit that I had plum cake for breakfast. . . . further signs of impending terminal decadence around here, especially since it is likely that I will do the same tomorrow.)
On second thought, maybe the plums do need a softer and more batter-y element to counteract their delicious acidity. Maybe I'll wait until next week (when we will be firmly and incontrovertably in apple territory for the duration of the fruit season) and make an apple cobbler.