How To make Kalter Kartoffelsalat (Cold Potato Salad)

6 ea Potatoes; Large *
1 x ;Boiling Water
1/2 ts Salt
1 ea Onion; Medium, Minced
3 tb Vinegar
1/2 ts Mustard; Prepared
1 ts Sugar
2 ts Dillseed
* Potatoes should be peeled and quartered. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ In medium saucepan cook potatoes in boiling salted water until tender. Drain, reserving 3/4 cup of potato water. Dice potatoes. Add oil and minced onion; toss gently. In small saucepan bring the 3/4 cup potato water to a boil; pour over potatoes and onion. Keep at room temperature for 2 to 3 hours. Stir in vinegar, mustard, sugar, and dillseed. Potato salad will be creamy. Serve at room temperature.