Kielbasa Grilled Cheese

Name: Kielbasa Grilled Cheese
Ingredients: 3 tablespoons sugar; 1/2 cup apple cider vinegar; 3 tablespoons vegetable oil; 1 16-ounce bag shredded coleslaw mix; 1/2 cup roughly chopped fresh herbs (such as parsley and dill); Kosher salt and freshly ground pepper; 8 ounces kielbasa, sliced diagonally 1/4 inch thick; 2 tablespoons whole-grain mustard; 8 slices rye bread; 8 slices cheddar cheese (about 6 ounces); 1/2 jalapeno pepper, thinly sliced (seeds removed for less heat); 2 tablespoons unsalted butter