In this picture I have the coasters arranged on a Christmas Table Runner I made from the same fabric.
To make them I cut a square of fabric 6 inches by 6 inches. I then cut a piece of wadding the same size and quilted the fabric to the wadding. In these examples I only used straight line quilting however my plan is to try free motion quilting when I make some non-Christmas ones. Just to try it.
Once the quilting was done I trimmed them to five and a half by five and a half inch squares. I then cut squares of the same size in the backing fabric (though they are reversible). I pinned the backing fabric to the quilted square, right sides together. Then I sewed a quarter inch from the edges all around, leaving a small gap to turn inside out. Trim the corners then turn right side.
Sew an eighth inch around all 4 sides. This tidies it up and also closes the gap I left to pull it the right way. My only negative was I don't like the finishing off of this last stitching. It looks a bit ugly on such a small piece if I sew back stitches at the start and finish. While it didn't bother me as much for these as they are just fun Christmas coasters I think it will bother me for any others so next time I will try finishing them off by not back stitching but burying the knot in the layers. I know it will be more time consuming but it will make me happier.
These can be made in any size of course and the same method used for placemats.