Today I made this strap clutch and added another layer of batting to the flap. I went back and forth whether to do this in the pattern, but in the end I didn't because the opening gets harder to sew the more layers of fabric you have in there. So I'll leave this as a personal preference and show it here for anyone who wants to add another layer.
Before adding this layer, go ahead and sew through (5.j) where you've made the openings on the A pieces and done everything except sew the facing pieces down (5.k).
Cut one piece A of interlining from batting/fleece/flannel or whatever you'd like to use. Place either the exterior flap A piece or lining A piece over the A interlining and trace around the strap opening outline.
Cut around the line about an extra 1/4" and trim the top corners of the piece just like you did for the interlining B pieces for the clutch body:
Then place this piece on the wrong side of either the exterior flap A or lining A. Pull the facing piece E through the opening of the interlining, smooth it in place and then sew around the opening.
You might want to trim the bottom of the facing to keep it out of seam at the bottom before sewing the A pieces together (6.c.). After you've sewn the seam around the sides and bottom, trimming any extra interlining back to close to the stitching will help make topstitching around the flap easier.
Tomorrow I'm taking pictures of how to install an eyelet for the opening.
