Prepare the cucumbers: Wash the cucumbers thoroughly. Using a sharp knife or a mandoline, slice them into thin rounds, about 3mm thick. You want them uniform so they all absorb the salt equally. The slices should look translucent around the edges.

Sweat the cucumbers: Place the slices in a large colander set over a bowl. Sprinkle over the fine sea salt and toss gently with your hands to coat every piece. Let them sit for 20 minutes. You will notice beads of water forming on the surface of the cucumber slices, and a pool of liquid will collect in the bottom of the bowl.

Rinse and dry: After 20 minutes, rinse the cucumber slices under cold running water to remove the excess salt. Taste one — it should be seasoned but not overly salty. Tip them onto a clean tea towel or a double layer of kitchen paper, pat them very dry, and feel how they have softened slightly but still retain a pleasant snap.

Make the dressing: In a medium mixing bowl, whisk together the sour cream, lemon juice, white wine vinegar, caster sugar, and black pepper. The mixture should be smooth, pale, and smell sharply of lemon and vinegar. Stir in the finely diced shallot.

Combine and rest: Add the dried cucumber slices and the chopped dill to the bowl of dressing. Fold everything together gently with a rubber spatula until every slice is coated in a creamy, speckled green dressing. The salad will look quite wet at this stage.

Chill and serve: Cover the bowl with cling film and transfer to the refrigerator for at least 30 minutes. This resting time allows the flavours to meld and the dill to infuse the cream. When you uncover it, the salad should look slightly thicker and smell wonderfully herbaceous. Give it one final stir, then transfer to a serving bowl and scatter over the chopped chives if using.