In a large bowl, thaw and crumble hash brown parries. Prepare bacon in large skillet over medium heat. Remove bacon from skillet; reserve drippings in same skillet. Using a wire whisk stir flour into bacon drippings until smooth. Add sugar, vinegar, water, salt, pepper, and celery seed. Stir mixtureuntil well blended. Contine heatingovermedium heat until mixture bouls and thickens. Add onions and crumbled bacon to mixture. Pour mixture over crumbled has brown patties. Stir to blend all ingredients. Make aheat and refrigerate to allow flavors to blend Heat and serve. Makes 8 (1 cup) servings.