Prepare and cut potatoes, celery, onions and dill.
In a large pot, put cut potatoes into water, and add 1 tablespoon of salt and stir.
Bring water to a boil and reduce heat to medium.
Cook for about 20 minutes (check at 15), or until desired firmness is reached.
Drain potatoes completely. Then rinse in colander and chill with cold water.
Refrigerate until potatoes are completely chilled throughout.
While potatoes are boiling, you can also boil the eggs in a separate pan by bringing water to a rolling boil, spoon each egg in, turn heat off and let them sit in the water for 10-12 mins.
Then, spoon eggs out of the water, rinse and soak in cold water to prevent them from cooking further. Then place into a bowl and refrigerate until chilled.
When they are completely chilled, remove shells from eggs and chop.
Combine chilled potatoes, chopped celery, chopped onions, fresh chopped dill, chopped hard-boiled eggs, mayonnaise, Dijon mustard. You can add any additional salt and pepper to taste now or before serving. Garnish with extra dill sprigs. You can serve right away or chill in the refrigerator overnight to fully marinate flavors.