In a large nonstick skillet (do not use iron, which discolors the Jerusalem artichokes), saute onion and celery in the butter until onion is transparent. Add Jerusalem artichokes, currants, and Bell’s seasoning; cook 5 minutes longer. Add stuffing cubes, chicken broth, grapes, parsley, and black pepper; toss gently to mix. At this point you can refrigerate the mix up to 24 hours.
Loosely stuff prepared turkey according to the directions on your bird. Put rest of stuffing in a covered buttered casserole dish and bake 30 minutes at 350 degrees F. Stuffing should reach 165 degrees F before serving.