Hot German Potato Salad

10 slices bacon
1 cup thinly sliced celery
3/4 cup chopped onion
5 cups sliced, cooked potatoes
3/4 cup water
1/3 cup vinegar
3 tablespoons sugar
2 tablespoons flour
2 teaspoons salt
3/4 teaspoon dry mustard powder
1/2 teaspoon celery seed
Dash ground black pepper
2 teaspoons chopped parsley

In a large, heavy skillet, fry bacon until crisp, drain bacon and save 1/2 cup bacon drippings. Add celery and onions to bacon drippings in the skillet, sauté until tender while stirring continuously. Add the potatoes and toss carefully. Combine and mix the water, vinegar, sugar, flour, salt, dry mustard, celery seed and ground pepper and pour it over the potatoes. Cook until thickened and warmed through, stirring carefully as needed. Sprinkle bacon and parsley over the top.