Roasted Kielbasa With Apples and Cabbage

Name: Roasted Kielbasa With Apples and Cabbage
Ingredients: 1 small red cabbage (about 1 ½ pounds), cut into 1 ½-inch-thick wedges; 2 small red onions, peeled and cut into 1-inch-thick wedges; 2 tablespoons extra-virgin olive oil; 5 tablespoons cider vinegar; 2 teaspoons caraway seeds; Coarse salt and freshly ground pepper; 3 small Gala apples (about 1 ¼ pounds), halved lengthwise and cored; 1 ½ pounds smoked kielbasa, slashed ¼-inch deep in a few places; Whole-grain mustard, for serving