Where did "cupcake" (and thus the dessert-based naming convention) come from?

I remember the G1 launch. A lot of people thought the phone was lame, because of a missing feature or the lack of apps compared to iPhone or whatever. When general users heard of this magical "cupcake" update, they started demanding it in app and blog comments, as if it would fix all the phone's shortcomings (apparently even improving the selection in the Market).

I know Cupcake was named after the code branch that had been in progress when 1.0 was launched, but wasn't yet ready at the time. I want more details. Who came up with it? Was it related to an inside joke? How long did it take to decide that future versions would also be named after desserts?

This matters not at all, but I'm still curious.