Mix flour, herbes de Provence, salt and pepper; rub over pork. In a large skillet, heat oil over medium-high heat. Brown roast on all sides. Place roast in a 5- or 6-qt. slow cooker. Add onions, apple cider, beef stock and bay leaves., Cook, covered, on low 3 hours. Add apples and dried plums. Cook, covered, on low 1-11/2 hours longer or until apples and pork are tender. Remove roast, onions, apples and plums to a serving platter, discarding bay leaves; tent with foil. Let stand 15 minutes before slicing.