Instead of using a large piece of expensive and pretty wool for the back I chose to use flannel, called woolies. It is a terrific substitute.
Sew around all four sides and trim the corners.
Make a slit on one fabric only. Make sure you slice it where your project will cover it up. As you can see, I wasn't concerned about a straight line.
Turn right sides out, push your corners out and press. Then applique your wool piece on top.
Ta-Da! Stand back and enjoy your handiwork!