How to Make It
Bring a large pot of water to a boil. Plunge the lobsters in headfirst and cook until bright red all over, about 10 minutes. Using tongs, transfer the lobsters to a large bowl. When cool enough to handle, twist off the claws and crack them all over. Remove the claw and knuckle meat and cut the claw meat into 1-inch pieces. Twist off the lobster tails. With a large, heavy knife, cut the tails in half lengthwise down the center. Pull out and discard the black intestinal veins. Loosen the tail meat but leave it in the shell. Cover all the lobster meat with plastic wrap and refrigerate.
In a small saucepan, combine the olive oil, basil, shallots and peppercorns and bring to a boil. Cover and simmer over low heat for 5 minutes, then strain the oil into a small bowl.
In a mini food processor, puree the plum tomato. Strain the tomato puree into the olive oil. Stir in the balsamic and red wine vinegars and season the tomato dressing with salt.
In a large bowl, toss the Boston lettuce, radicchio and mâche with the lobster-claw and knuckle meat. Add all but 2 tablespoons of the tomato dressing and toss well. Mound the salad on plates and arrange the tomato wedges alongside. Top each salad with a halved lobster tail, cut side up. Brush the tail meat with the reserved tomato dressing and serve at once.