Ingredients

• 4 (1 1/2-lb) live lobsters or 1 1/2 lb cooked fresh lobster meat
• 1 lb small red potatoes
• 3 ears corn
• 2 1/2 tablespoons fresh lemon juice
• 1 1/2 to 2 tablespoons chopped fresh tarragon
• 1/2 teaspoon Dijon mustard
• 1/2 teaspoon salt
• 1/4 cup extra-virgin olive oil
• 2 cups grape or cherry tomatoes, halved
• 1 cup coarsely chopped frisée (French curly endive)
• 1/3 cup sliced scallion

Instructions

1. Plunge 2 live lobsters headfirst into an 8-quart pot of boiling salted water. Cover and cook lobsters over moderately high heat 9 minutes from time they enter water, then transfer with tongs to sink to cool. Return water to a boil and cook remaining 2 lobsters in same manner. Leave water boiling in pot.
2. Simmer potatoes in lobster cooking water until just tender, 15 to 20 minutes. Transfer with a slotted spoon to a colander, reserving boiling water in pot.
3. Boil corn in same water until crisp-tender, about 3 minutes, then drain.
4. When lobsters are cool, remove meat from claws, joints, and tails, reserving shells for another use.
5. Cut meat into 1-inch pieces. Cut potatoes into 3/4-inch pieces, and cut corn from cobs.
6. Make vinaigrette: Whisk together lemon juice, tarragon, mustard, and salt until combined, then add oil in a thin stream, whisking.
7. Whisk together lemon juice, tarragon, mustard, and salt until combined, then add oil in a thin stream, whisking.
8. Assemble salad: Just before serving, toss together lobster meat, potatoes, corn, vinaigrette, tomatoes, frisée, and scallion in a large bowl and season with salt and pepper.
9. Just before serving, toss together lobster meat, potatoes, corn, vinaigrette, tomatoes, frisée, and scallion in a large bowl and season with salt and pepper.