Also called a Channel Seam. Purely decorative. Two finished edges that open to reveal the same or contrasting fabric.
1. Right sides of fabric together, pin along stitch line.
2. Machine baste seam together.
3. Press to set stitches. Press open. Press from front.
4. Cut a strip of matching or coordinating fabric the width of the two seam allowances pressed open (for ½” wide seams, strip should be 1”). This strip could be on bias (pulled) or straight of grain.
5. From the face, stitch an equidistant amount from the original seam (within the seam allowance), through all three layers of fabric.
6. Remove basting stitch.
7. Press to set stitches.
8. Finish raw edges of seam allowance as desired (ex. Stitch and Pink, Serge, Hong Kong Finish, Bound Finish, etc.). Press to set stitches.