I started from a basic bodice block, and added two half ovals for the sleeves, and a wide rectangle at the hips for a peplum effect. The bodice is fully lined, with a blind zipper in the back (I know I'm predictable).
Often flutter sleeves are finished off with a serger or a zigzag stitch, but I like a clean and crisp look better, so I lined the sleeves.
The entire process (pattern drawing + sewing) took me just 3 hours. Flutter sleeves ROCK.