Place the potatoes in a Dutch oven and cover with water. Bring to a boil, then reduce the heat, cover, and simmer for 25–30 minutes, or until the potatoes are tender.

Drain the potatoes and allow them to cool enough to handle.

While the potatoes are cooking, cook the diced bacon in a large skillet over medium heat until crisp. Remove the bacon with a slotted spoon and drain on paper towels. Reserve 4 tablespoons of the bacon drippings in the skillet.

Add the chopped onion to the bacon drippings and sauté until tender.

Stir in the flour, salt, celery seed, and pepper until well combined.

Gradually stir in the sugar, cider vinegar, and water. Bring the mixture to a boil over medium-high heat and cook, stirring constantly, for about 2 minutes, or until the dressing has thickened.

Cut the cooled potatoes into ¼-inch slices and add them to the skillet along with the cooked bacon.

Cook over low heat, gently stirring, until the potatoes and bacon are heated through and coated with the dressing.

Sprinkle with fresh parsley and serve warm.