In a large, 2-gallon stockpot filled with 1 1/2 gallons of water, place the onion, carrot, celery, bay leaves, lemon juice and rind, peppercorns, and salt. Bring the pot to a boil and cook for 15 minutes. Place the lobster tails in the water and cook for 3 1/2 to 4 minutes. Remove the lobsters from the boiling water and cool in an ice bath immediately. Once the lobsters are cool enough to handle, remove the tails from the shells and use a chef's knife to cut the tails in half lengthwise.

To prepare the salsify, wear rubber gloves. (Salsify releases a milky sap when peeled.) Using a vegetable peeler, peel the salsify. Use a sharp paring knife to trim the ends. Cut the salsify into 2-inch lengths and place in a non-reactive bowl with 4 cups of cold water and the white vinegar. In a medium saucepan, combine the milk, water, 1 teaspoon of the salt, and 1/2 teaspoon of the black pepper. Place the salsify pieces in the pan and bring to a boil, reduce the heat to a simmer and cook for 15 minutes. Remove from the liquid and set aside to cool. Once cool enough to handle, sprinkle the salsify with the cornstarch. Shake to release any excess cornstarch. Heat a large saute pan over medium-high heat and add 1 tablespoon of the olive oil to the pan. Once the oil is hot, place the salsify in the pan and sear for 1 minute. Add 2 tablespoons of the butter to the pan and turn the salsify over on to the other side. Continue to sear the salsify, turning occasionally, until all sides are evenly browned. Add the chervil leaves and toss until coated. Remove the pan from the heat and set aside until ready to serve.

Place a 10-inch saute pan over medium-high heat and add the remaining tablespoon of olive oil to the pan. Once the oil is hot, place the lobster tails, cut-side down in the pan and sear for 2 minutes. Add the remainding two tablespoons of butter to the pan and continue to sear the lobster for another 2 minutes. Turn the lobsters and cook for 30 seconds on the other side. Remove from the pan and set aside.

Assemble plates by dividing the salsify evenly among 4 plates. Top each portion of salsify with one piece of lobster tail. In a small mixing bowl, gently toss the mache with the extra-virgin olive oil and remaining salt and pepper. Place 1/2 cup of the mache on top of each lobster tail and serve immediately.