Warm potatoes soak up every last drop of flavour from the vinaigrette.
Add garlic and fresh herbs to the vinaigrette for extra taste.
Boil potatoes until they are done but still firm. Make the dressing by whisking together the oil, lemon juice, Dijon and salt and pepper. Pour the dressing over potatoes when they are still warm. Let cool.
Slice the spring onions and radishes. Combine potatoes, onions, radishes, cheese and chopped dill. Season with salt and pepper and serve, luke-warm or cold.