I've done quilted pot holders in the past, but had never thought of combining knitting and fabric.
The front is knitted in Superwash Pure Merino Double Knitting Wool. The backing is 100% cotton, with two layers of batting. I've used a layer of Dream Cotton along with heat resistant batting. This gives a lovely padded surface, and helps with the heat resistance.
Now I've done it once, I think there may be more of these in the future. With some of this yarn left over, there is already one more waiting in the wings.