Balsamic Potato Salad

Cook potatoes in large pot of boiling salted water over medium heat until just tender.

Meanwhile make balsamic dressing. Whisk sour cream, vinegar, olive oil, salt and pepper in a large bowl until blended.

Stir in all but 2 tbsp. sliced scallions. Drain potatoes well in colander.

Transfer to bowl, add dressing and gently toss to coat.

Let potatoes cool to room temperature. Add celery and radishes to potatoes and toss gently to combine. Line serving bowl with romaine leaves and spoon potato salad onto lettuce.

Sprinkle salad with reserved scallions.