Smoked herring, pickled red onion & mustardy potato salad

Prepare the pickled onions. Add the onion and the juice of 1½ lemons to a small bowl, season with salt and set aside. This could be done in advance and will keep, covered, for up to 3 days in the fridge. Simmer the potatoes in salted water for 10-15 minutes until tender. Once cooked, drain, and let them steam dry for a few minutes.

Meanwhile, make the dressing. In a bowl large enough to hold the potatoes, add the mustard, the remaining lemon juice and the chopped dill, then season generously with salt and freshly ground black pepper. Whisk together, slowly drizzling in the oil.

When cool enough to handle, break the potatoes in half, add to the dressing and toss well. Taste and season, if needed.

Plate mounds of the dressed potatoes, flaked herring fillets (discard the skin and any large bones) and dill fronds alongside one another, with the drained pickled onions in the middle. Finish with more oil, then season again, if you like.