Spray slow cooker with cooking spray. In slow cooker place turkey breasts halves. Sprinkle with salt and pepper.
Cover; cook on low 7-8 hours.
Remove turkey from slow cooker; cool slightly. Remove 2/3 c juices from slow cooker; place in 1 qt saucepan. Add soup; mix well. Cook over medium heat about 5 minutes; stirring occasionally, until hot.
To serve, cut turkey into slice; place on bottom halves of buns. Pour gravy over turkey. Cover with top halves of buns. Serve sanwiches with cranberry sauce.