Potato Salad with Honey-Buttermilk Dressing

In a medium saucepan, cover the potatoes with cold water and bring to a boil. Reduce the heat to moderately low and simmer until the potatoes are tender, about 20 minutes. Drain the potatoes and let cool slightly, then cut into 1/2-inch dice.

Meanwhile, in another medium saucepan of boiling salted water, cook the green beans until crisp-tender, about 6 minutes. Drain the beans in a colander and refresh under cold water. Drain well and pat dry.

In a large bowl, mix the buttermilk with the honey, parsley, chives, shallots, vinegar, mustard, tarragon, scallion and lemon zest. Season with salt and pepper. Add the radishes and beans; toss to coat. Add the potatoes, season with salt and pepper and toss the salad gently. Transfer the salad to plates and serve at room temperature.