Step 1

Put the potatoes in a large pot, cover with water, bring to a simmer and cook until tender.

Step 2

Pour them into a colander and cool slightly. Start peeling the potatoes before they cool completely as the skin sticks to them more when they're cold.

Step 3

For the dressing, mix the buttermilk, horseradish, the juice of one  lemon, salt, pepper and olive oil well.

Step 4

Cut the potatoes into 1cm rounds and place them in a mixing bowl with the celery and chives. Pour enough dressing over to coat the salad well.

Step 5

Pour into a serving bowl and grate zest from remaining lemon over the salad.

Step 6

If you can find them, chive flowers make a nice finishing touch.