1. Place a large nonstick skillet over medium-high heat. Add chopped onion, and sauté 5 minutes or until tender.
2. Place onion, peaches, and next 7 ingredients (through cloves) in a 3-quart electric slow cooker; stir well. Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and vinegar in a small bowl; stir with a whisk until well blended. Add flour mixture to peach mixture; stir well. Cover and cook on LOW for 5 hours.