It's backed in a very pretty soft argyle flannel. I've never quilted with flannel before, but I read some recommendations and did pre-wash the flannel (I don't pre-wash my quilting fabrics - ssshhhhh, don't tell!) since I was afraid it would shrink much more than the cotton quilting fabric. That seems to have worked well and I think I will use the same method on my next two quilts that I have flannel backs for. I did wash the whole quilt today after I finished the binding - and the back was not too loose or too taut.
I quilted this one with spiraling squares inside each square. I used my walking foot to help with the flannel feeding with the rest of the quilt. It worked well for me!
One of the squares has an appliqued "a" for the little girl who is getting this for her birthday. I did free-motion around the "a" to make it stand out a bit.