Instructions

1. 1
   Boil the potatoes with 1 tablespoon salt (and 1 tablespoon caraway, if using) until cooked but still fairly firm. Drain, rinse, let cool slightly, and peel while lukewarm.
2. 2
   In a large sealable jar, combine the mustard, sugar, pickle juice, vinegar, oil, a little salt, plenty of pepper, and the finely chopped onion (and garlic if using). Shake vigorously to make a vinaigrette emulsion.
3. 3
   Peel and finely chop the apple if using; slice the pickles; slice the lukewarm potatoes.
4. 4
   Layer the potato slices, pickles, and apple in a large bowl, spooning some vinaigrette and a little salt and pepper between the layers.
5. 5
   There should be slightly too much marinade in the salad. Let it soak at least 3-4 hours, ideally overnight - the potatoes absorb the marinade and stay juicy without getting mushy. Mix well before serving.
6. 6
   Garnish with green onions or chives.