Haricot Vert, Edamame, and Purple-Potato Salad

1. Have ready a large bowl of ice and cold water. Boil edamame in a large pot of boiling salted water until crisp-tender, 1 to 3 minutes. Transfer with a slotted spoon to ice water. Shell edamame.
2. Bring potatoes and enough salted water to cover by 1 1/2 inches to a boil and cook at a bare simmer until almost tender, 15 to 20 minutes. (Potatoes will continue to cook a bit after being removed from water. Be careful not to overcook or potatoes will break apart when sliced.) Transfer with a slotted spoon to ice water to cool. Drain well.
3. While potatoes are cooking, trim haricots verts and halve diagonally crosswise. Cook in 2 batches in a large pot of boiling salted water until just tender, 3 to 4 minutes (regular green beans will take longer to cook). Transfer to ice water to cool. Drain well.
4. Just before serving, cut potatoes into 1/3-inch-thick slices and toss all ingredients together in a large bowl with salt and pepper to taste.

Yield: 16 servings