Add the red cabbage and vinegar, and stir until combined. Then add the apple cider, jam (optional), cloves, bay leaf, and juniper berries. Season with sugar, salt, and pepper.
2 pounds red cabbage, 3 tablespoons apple cider vinegar, 1 cup apple cider, 1 tablespoon lingonberry jam, 2 cloves, 1 bay leaf, 2 juniper berries, 1 tablespoon white sugar, ½ teaspoon salt, ¼ teaspoon pepper