I'm not sure how authentically French this salad really is, but I envisioned it after purchasing pristine green beans and fingerling potatoes last week. It's at least European of me to plan my dinner around whatever looks good at the market, right?
The salad is a lazy hybrid of salade Niçoise (named for une citeé en Provence) and sauce gribiche (a delicious concoction involving mayonnaise, capers, cornichons–-none of which appear here--and hard-boiled egg yolks--which do), and helped me legitmize the purchase of brie with my mom's credit card. Hey, she helped me eat it.
Look for beans that are crisp and rigid, and potatoes with smooth skin that peels back when you rub it. Wash and pat dry the potatoes and slice them into half-inch rounds or bite-sized chunks, and remove stem-ends from the beans (if they're really young and slender, this isn't necessary). Then, briefly blanch batches of each in salted (at least 1 tsp), rapidly boiling water: 1 min for the beans, about 5 for the potatoes. The beans should remain crisp and be vivid green, the potatoes should yield to a fork but not be mushy.
Once removed from boiling water and cooled to near-room temperature (plunge beans into an ice-water bath if you're afraid of overcooking), toss potatoes and beans in a large bowl with the following ingredients: sliced hardboiled eggs (or 1-2 per person), diced red onion, and enough mustard vinaigrette to coat but not overpower the veggies (in other words, to taste). I made mine with grainy Dijon, red wine vinegar, olive oil, salt and pepper, and a pinch of fresh chopped tarragon.
Serve with bread, brie, and chardonnay for a petite, frenchified dinner.