French Potato and Chicken Salad

1 pound uncooked red potatoes, small, scrubbed
1 spray cooking spray
2 pounds uncooked boneless, skinless chicken breast
3/4 pounds green snap beans
2 medium celery, stalks, thinly sliced
4 oz grapes, green, seedless, halved (about 1 cup)
1/4 cup fresh lemon juice
1/4 cup reduced-sodium chicken broth
1 Tbsp Dijon mustard
3 Tbsp fresh tarragon, leaves, chopped
1/2 tsp table salt
1/4 tsp black pepper, freshly ground
1/4 cup olive oil

Place potatoes in a large pot of boiling water over high heat; cook until tender when pierced with a fork – about 20 minutes. Using a slotted spoon or strainer, remove potatoes from water and set aside but maintain waters boil.

Meanwhile, coat broiler rack with cooking spray; preheat broiler. Broil chicken five inches from heat, turning occasionally, until cooked through – about 10 minutes; set aside

Add green beans to boiling water and blanch until tenderly crisp – about 1 1/2 to 2 minutes; using a colander drain over sink.

Slice cooled chicken into bite-size chunks and place in a large serving bowl. Slice potatoes into 1-inch chunks and cut green beans into 1-inch pieces; gently toss with chicken. Add celery and grapes.

To prepare the dressing: in a small bowl, whisk lemon juice, broth and mustard; whisk in tarragon, salt and pepper. Drizzle in oil in a slow stream, whisking all the while, until dressing turns creamy, about 1 minute. Toss salad with dressing, taking care not to break up potatoes. If desired, cover and refrigerate for up to 2 days.