3 lbs. lean short ribs
3 T. vegetable oil
4 medium baking potatoes, unpeeled and quartered
4 carrots, peeled and cut into pieces
1 medium onion, sliced
1 (14 1/2 oz.) can beef broth
2 T. white vinegar
2 T. ketchup
1 T. prepared horseradish
1 T. prepared mustard
1 t. salt
1/4 t. pepper
Brown ribs in hot oil in a large skillet 5 to 6 minutes on each side; drain.
Place potatoes, carrot pieces, and onion slices in a 5-quart electric slow cooker, and arrange ribs over vegetables.
Combine 1 cup broth, the vinegar and next five ingredients; pour mixture over ribs and vegetables. Cover and chill remaining broth.
Cover and cook on HIGH 3 to 3 1/2 hours, OR cook on HIGH for 1 hour, reduce heat to LOW and cook 7 more hours. Remove ribs and vegetables, reserving liquid in slow cooker. Keep ribs and vegetables warm.
Combine remaining chilled beef broth and flour, stirring until smooth; stir into reserved liquid in slow cooker. Cook on HIGH setting, uncoverd 10, minuted or until thickened, stirring often. Serve w/ ribs and vegetables.