Creativity and timeframe

As legal scholars turn their attention to the nuts and bolts of creativity, I've seen a couple of people discuss creativity as process v. product and the related question of when creativity happens--flash of genius or organic evolution, or both and neither?  Here's an anecdote of possible relevance:

[Moon River, from Breakfast at Tiffany's,] was one of the toughest I have ever had to write. It took me a month to think it through.  What kind of song would this girl sing? What kind of melody was required? Should it be a jazz-flavored ballad? Would it be a blues?  One night at home, I was relaxing after dinner. I went out to my studio off the garage, sat down at the piano ..., and all of a sudden I played the first three notes of a tune.  It sounded attractive. ... It came quickly. It had taken me one month and half an hour to write that melody.

 Henry Mancini, Did They Mention the Music? (1989) (excerpt) in The Hollywood Film Music Reader, ed. Mervyn Cooke (2010)