Green Bean, Potato And Leek Salad
["8 medium-small red potatoes", "1 lb. green beans, trimmed and halved crosswise", "1 Tbsp. Dijon mustard", "3 Tbsp. white wine vinegar", "1/2 c. vegetable oil", "2 Tbsp. (1/4 stick) butter", "4 leeks (white part only), halved lengthwise and thinly sliced crosswise", "chopped fresh parsley", "3 hard-boiled eggs, shelled and quartered (optional)"]
["Boil or steam potatoes and green beans separately until tender but not mushy.", "Drain or remove from steamer.", "Cut each potato into eighths.", "Place in salad bowl. Add green beans.", "Blend Dijon mustard and vinegar in small bowl.", "Whisk in vegetable oil in thin stream.", "Pour over potatoes and beans; mix gently to coat.", "Season salad to taste with salt and pepper. Set aside."]
["red potatoes", "green beans", "mustard", "white wine vinegar", "vegetable oil", "butter", "leeks", "fresh parsley", "eggs"]