This Doll's Vest isn't as quick as the Half Circle Skirt; however, in under an hour, you'll be able to stitch this up and have a gift at the ready for your favorite American Girl (or any other 18") Doll.
You'll spend most of your time turning this tiny vest. Be very careful to follow the instructions regarding WHICH seams you sew. If you accidentally stitch up the side seams, you'll be using words no one likes to hear. ;o)
There is a bit of hand-stitching involved, though nothing extreme. You'll just need to use a slipstitch or whipstitch to close up the lining.