You will need a large skillet for stewing plums. For best results, use a skillet large enough to fit all the plum halves in a single layer (mine was 12 inches), and use one that has higher sides to contain the cooking liquid. After testing this recipe using a saucepan, as I did for my recipe for stewed peaches, I was feeling frustrated because the plums were breaking apart as they cooked. So, I switched to using a large skillet, which worked wonderfully because it allowed the plums to cook in a single layer, helping them to stay intact as they cooked.