Step 1: Gather Materials
3 yards (or more) of any flannel cotton fabric in two colors (make sure none of them will bleed on the other)
Paper to make a pattern
Basic sewing supplies
--Chalk or fabric marker
--Matching thread for both colors
Step 2: Create Cape Pattern
From the tip of your shoulders, using a straight-edge ruler, draw a straight line at a slight angle, creating an A-line effect from your shoulders. The length of the cape is at your preference.
Draw a straight perpendicular line for the bottom edge.
For the neck hole, I used a plate from my kitchen to create the curve of the front neck hole and the back neck hole. The back neck hole should be higher than the front neck hole.
Finally, using a straight-edge ruler, draw a straight line near the edge of the A-line to mark the place of the armholes. I made mine 18 inches long.
Step 3: Cut Out Fabric
For the back pieces, fold the fabric, place the pattern on the fold, and cut out. Make sure to cut the neck hold with the upper curve of the pattern.
Transfer the end points of the arm hole line onto the front pieces of the fabric only.
Step 4: Start Sewing
You should have two capes now.
Try on each cape and make sure the cape drapes nicely on the slope of your shoulders. Alter if necessary.
Step 5: Create Fabric Pieces for Clasp Closure
Using the leftover fabric, create two rectangle pieces on each fabric. The length doesn't matter as much as the width, but the width must measure twice the width of the closure opening.
For each rectangle piece, fold the piece in half length-wise, right sides together, and sew using a 1/4 seam allowance. Turn inside out and press.
Place one fabric piece inside the other--right sides together-- and sew on one end only.
Turn inside out and feed it through the clasp.
Step 6: Sew the Capes Together
Place the fabric of the clasp 1/2 to 1 inch down the vertical edge of the front piece and pin in place. Right sides should be together and the magnetic clasp should be in the body of the fabric.
With right sides together, pin and then sew the two capes together along the sides and neck hole of the capes. Do not sew yet on the bottom edge of the cape.
Turn everything right side out when finished.
Then hem along the bottom edge of the cape.
Step 7: Create Armholes
I switched the settings on my sewing machine to a zig-zag stitch with a setting of 4 for the width and 0.4 for the length.
The top stitch thread on the sewing machine should match the color of the fabric on top, and the bottom or under stitch (the bobbin) thread should match the color of the fabric on the bottom.
Match up the endpoints of armhole and pin through all layers of fabric to hold in place.
Create a long rectangle using the zig-zag stitch.
When finished, using fabric scissors, carefully cut out the fabric inside the rectangle.
You should now have armholes for your cape.