15g chopped fresh mixed herbs (such as chives, dill, and parsley)
50g soured cream
100g green beans, topped and halved
½ cucumber, quartered lengthways and sliced
4 cornichons, chopped
2 Little gems lettuces, quartered
Mix the vinegar, sugar, and salt in a bowl. Add the red onion and set aside for at least 20minutes, stirring occasionally and pressing down into the pickling liquid.
In a large saucepan, boil the potatoes for 20minutes or until tender. Drain well, steam-dry for 2minutes, then halve.
In a large bowl, whisk the mustard with 2tbsp vinegar from the onions and the oil until emulsified, season. Add the potatoes and stir to coat. Set aside for 5minutes to absorb the flavours, then stir in the herbs and soured cream
Boil the eggs for 8 minutes, adding the green beans for the final 3 minutes. Drain, run under cold water (to stop the cooking process), then peel the eggs and quarter.
Add half the pickled onion (discarding the vinegar) to the potatoes along with the beans, cucumber, cornichons, and quartered Little Gem lettuce. Gently mix together, then spoon onto a serving platter / bowl and top with the eggs and remaining onion.