This classic French salad, with its vibrant composition of fresh and cooked vegetables, unctuous oil-cured tuna, anchovies, and soft-boiled eggs, is filling enough to be a meal. Chef Boulud offers two options for dressing: a simple garnish of lemon and oil, or his grandmother's cherished vinaigrette recipe.
Potatoes: Fill a small saucepan with water. Add potatoes, thyme sprig, bay leaf, and a pinch of salt. Bring to a boil, reduce to a simmer, and cook until tender, about 15 minutes. Haricots vert: Fill a large saucepan with water and bring to a boil. When boiling, add a big pinch of salt, followed by haricots verts. Cook until tender with a slight snap, 4–9 minutes depending on size. Eggs: Fill a small saucepan with water and bring to a boil. When boiling, use a spoon to gently ease eggs into the water. Cook exactly 7½ minutes. Meanwhile, prepare two ice baths: Fill two large bowls with water and plenty of ice.
Scallions: Trim away the very end of the root while keeping scallion intact; remove the thick outer layer. Cut away the dark green top, leaving a 3-inch length of white and light-green scallion. Make several 1-inch vertical cuts down the top to create a scallion "brush." Repeat with all the scallions and place them in an ice bath to preserve freshness. Radishes: Slice each radish lengthwise into thin slices. Set aside.
When beans are mostly tender with a touch of firmness, use a strainer to transfer them to an ice bath to stop the cooking. Remove eggs and place them into the same ice bath. Check potatoes for doneness by piercing one with a knife; there should be no resistance. Remove potatoes and set aside; discard thyme and bay leaf. Peel eggs, slice in half lengthwise, and set aside.
Assembly: On a serving platter, layer the Boston lettuce, followed by the baby gem. Slice potatoes in half lengthwise and distribute evenly, followed by haricots verts, scallions, whole tomatoes, radish, large chunks of tuna, and eggs. Garnish with leaves of basil and chervil.
Pit olives (optional): Place olives on a flat surface. Press the bottom of a small bowl on the olives to loosen their pits; remove and discard the pits. Scatter the pitted olives over the salad. Next, tuck small bunches of arugula within the lettuce. Finally, finish assembling the salad by laying about 10 anchovies evenly across the top.
Chef Boulud offers two options for dressing the salad. Lemon & Oil Dressing: Zest lemon evenly over the salad, then sprinkle with lemon juice. Drizzle with olive oil, and finish with pepper and salt. (Note: Use salt with moderation, since the tuna and anchovies are already salted.) Grand-Mère’s Vinaigrette: In a bowl, add the sliced garlic and a pinch of salt. Use a fork to mash the garlic into a coarse paste. Add mustard, vinegar, and pepper; stir to combine. Add olive oil in a slow stream, whisking constantly with the fork to emulsify. Add a teaspoon of water at a time, whisking between additions, to thin vinaigrette as desired. Place vinaigrette into a serving dish and serve alongside the salad.