potatoes, cooked and diced
apple cider vinegar
Cook the potatoes, leaves the skin on and dice into 1/2 to 1 inch chunks.
Fry the bacon until crisp, reserve 1/4 cup of the fat, crumble the bacon.
Saute onion in the reserved bacon fat, add flour, stir in vinegar,water,sugar,salt,pepper,mustard, and rosemary. Cook to medium thickness.
Pour over the potatoes, add the crumbled bacon and mix carefully. Serve hot, refrigerate leftovers which can be reserved either hot or cold.