Classic potato salad

Put potatoes in a large pan of cold, salted water and bring to
the boil. Simmer for 15 minutes, or until tender. Meanwhile, put onion and vinegar in a large bowl, then cover and set aside.

Drain potatoes and return to pan off the heat, then set aside
for 5 minutes to steam-dry. Slice potatoes into bite-sized pieces and add to onion mixture, then season with salt and toss to combine. Cover and chill until cold.

Put sour cream, mayonnaise and mustard in a bowl and stir to combine, then add to cold potatoes with celery, gherkin and dill. Stir until well combined, taking care not to break up potatoes too much. Season to taste, then chill for 1 hour before serving.