Berliner Potato Salad (Berliner Kartoffelsalat)

Make sure onion, pickles and apple are chopped the same size.

Boil the potatoes with their skins on until tender, about 20-30 minutes.

Remove from pot and let rest until cool enough to handle but still warm, then peel and dice into preferred size.

In a bowl, combine all the ingredients except potatoes.

Put potatoes into a big bowl, pour "sauce" over them and stir together carefully (potatoes break apart easily while still warm). Cover bowl and let rest in refrigerator for at least 2 hours (overnight is even better).

Taste test and add more pickle juice, salt, pepper, sugar or mayonnaise if/as needed.