In a 3-quart saucepan, cook bacon till crisp. Drain bacon, reserving drippings in pan. Set bacon aside. Cook the chopped onion in bacon drippings till tender but not brown. Add the potatoes, corn, 1-1/2 cups of the chicken broth, the celery, salt, and pepper. Bring to boiling. Reduce heat; cover and simmer for 15 to 20 minutes or till vegetables are tender.
Combine flour and remaining 1/2 cup chicken broth; add to vegetable mixture. Cook and stir till thickened and bubbly. Reduce heat to low. Stir in buttermilk; heat through but do not boil. Top each serving with some of the bacon. Garnish with paprika or snipped parsley, if desired. Serve immediately.