Take 2 really nice matching placemats and one thick one. Sew the thick one on all 4 sides to one of the matching placemats, run a seam or FMQ it to the bottom so it won't slide. Then place the other matching placemat on top of it and sew it on 3 sides only, leaving one short end unsewn. Add 2 buttons and buttonholes or velco: now you have a casserole carrier.