Boil the potatoes in their skin in enough salted water to cover the potatoes until fork tender about 20 minutes. Begin checking at 15 minutes because smaller potatoes could be done sooner. Drain and allow to cool so that they can be handled and peeled.
In a skillet, cook the bacon until crispy. Drain bacon on a paper towel and save about 2 tablespoons of the rendered fat. Chop the cooked bacon and set aside.
While potatoes are cooking, dice onion and chop dill and parsley.
In a separate bowl, mix chicken stock, sugar, salt, pepper and vinegars.
Peel potatoes and cut in half, then in ¼-inch slices. Place in large mixing (or serving) bowl. Pour the vinegar mixture over the potatoes and stir gently to incorporate. The warm potatoes will soak up dressing.
Add the bacon, onion and herbs. Add the reserved bacon fat and stir gently again.
Let sit for about 5 minutes, then add oil. Start with ¼ and fold in gently. Then add remaining oil. The mixture will be soupy at the bottom but over the next 15 or 20 minutes, the potatoes will soak it up.
If you’ve saved any parsley or bacon bits, sprinkle them over just before serving.
German potato salad is best served warm or at room temperature.