Cook noodles according to package directions.

     Meanwhile, in a skillet, cook the bacon until crisp.  Crumble and set aside.  Reserve 1 T. drippings in the skillet; sauté onion until tender.  Stir in sugar, flour, salt, and mustard; add water and vinegar. 

     Cook and stir until thickened and bubbly, about 2-3 minutes.  Rinse and drain noodles; add to skillet.  Stir in celery and parsley, heat through. 

     Transfer to a serving bowl; sprinkle with bacon.