9 medium-size red potatoes, scrubbed (about 4 1/2 lb.)
6 slices bacon
1 medium onion, finely chopped
2 tbsp. all-purpose flour
2 tbsp. sugar
2 tsp. salt
1/8 tsp. pepper
1/2 tsp. celery seeds
3/4 c. water
1/2 c. apple cider vinegar (red)

Cook potatoes in boiling water to cover 25 to 30 minutes or until tender. Drain and cool 10 to 15 minutes; cut into 1/4-inch thick slices and set aside. Cook bacon in a large skillet until crisp; remove, reserving drippings in skillet. Crumble bacon and set aside. Cook onion in reserved drippings, stirring constantly, until tender. Add flour and next 4 ingredients, stirring until blended. Cook about 1 minute over medium heat, stirring constantly. Gradually stir in water and vinegar; cook until sauce is thickened and bubbly. Layer 1/3 of potatoes and bacon in a 2 1/2-quart bowl; drizzle with 1/3 of the sauce. Repeat procedure twice, ending with sauce.