the freezer paper. trim your quarter inch seam.
now lay the two pieces right sides together, if you trimmed properly, you should be able to line the top and bottom of the pieces up and have accurate results. pin the pieces together in the seam allowance.
sew right along the edge of the freezer paper. if everything was lined up right, you should also be sewing along the edge of the freezer paper on the bottom.
open up the block and iron the seam. i ironed this one open since there is a lot of bulk.
turn your block over and admire your work.
the freezer paper on the back can now be peeled off. 