A warm potato salad is a useful alternative to a bowl of cold potatoes buried in dressing. The dressing can be fairly simple because the potatoes take it in rather than merely wearing it.
Boil 500 g small potatoes until a knife enters without resistance. Cook 200 g trimmed green beans separately until tender to your liking. Whisk two tablespoons olive oil with a tablespoon lemon juice and a teaspoon mustard.
Drain the potatoes, let the excess steam escape briefly, then halve and toss with the dressing while warm. Add the beans and chopped parsley. Season after tasting a piece of potato, not just the dressing at the bottom.
Serve as two light meals with white beans or as a side dish. If making it ahead, cool and refrigerate promptly. Warm service does not mean leaving it on the counter all afternoon; bring together the cooked components when you intend to eat.