Our Family'S Pennsylvania Dutch Potato Salad - cooking recipe

Ingredients

Salad Ingredients
3 lbs medium red potatoes (about 18-20 potatoes)
1 cup onion, chopped (vidalia onion is preferred now)
1 cup celery, chopped
2 teaspoons salt
1 teaspoon pepper
6 slices bacon, cooked crisp and diced (save bacon drippings in a small measure)
2 -4 slices bacon, cooked crisp and diced (do not save these drippings)
Dressing ingredients
bacon drippings, from the 6 slices of bacon only (see above)
3/4 cup apple cider vinegar
1/8 - 1/4 cup sugar (to taste)
6 tablespoons water
1 egg, at room temperature, well beaten

Preparation

Cook the 6 slices of bacon in fry pan until crisp, remove from pan and drain on paper towels before dicing. Reserve the bacon drippings in a small measure from these 6 slices. Then cook the remaining 2-4 slices until crisp, remove from pan and drain on paper towels but do not reserve this additional drainings.
Cook potatoes in boiling water until just tender -- do not overcook.
Cool potatoes slightly then peel and cut into medium sized chunks and place into a large bowl.
Add onions, celery, salt and pepper to potatoes and mix lightly (so you do not break up the potatoes).
Mix vinegar, sugar and water with cooled bacon drippings in the fry pan.
Heat mixture just to simmering - over a medium heat.
In another bowl, crack open egg and beat well with a whisk.
Very slowly, add the dressing mixture to the beaten egg, whisking constantly.
Pour dressing over potatoes and then add bacon and mix lightly.
Serve warm.