Place the potatoes in a pot of water with some salt and bring to a boil. Boil until the potatoes are soft, which takes approximately 20 minutes.
In the meantime you can hard boil the eggs, which should take between 8-10 minutes. Leave to cool completely before using.
Prepare the stock/broth.
Peel the onion and chop up into cubes. Fry the onions on a low heat for approximatley 10 minutes.
Stir in the mustard and vinegar with the broth until combined.
Chop the dill finely and cube the pickled gherkins. Peel the eggs and slice into cubes.
Once the potatoes are boiled, peel them and then slice them into bitesize pieces.
While the potatoes are still warm, place them in a large salad bowl and pour over the still-warm stock/broth mixture. Stir and season with salt and pepper to taste.
Add the gherkins and eggs and leave the rest for approximately 2 hours. You can leave it in the fridge or leave to rest at room temperature.
Before serving add the mayonnaise and yoghurt to the salad. Lastly add in the dill and mix into the salad.