Preheat the oven 375 degrees F. Oil 12 (4-ounce) ring molds.
In a food processor, fitted with a metal blade, combine the fish, egg whites, Cognac, chives, shallots, lemon juice and nutmeg. Puree until smooth.
Add enough cream so the mixture is smooth but slightly thick. Season with salt and pepper.
To test the seasoning, bring a small pot of water to a simmer. Add a teaspoon of the mouse to the water and poach for about 2 minutes. Remove and taste. Adjust the seasoning according to taste.
Fill each mold with the fish mixture.
Place the molds in a baking dish and fill with water, enough to come up 1-inch of the mold. Place in the oven and cook for about 12 to 15 minutes or until firm. Remove from the oven and cool completely.
Refrigerate until chilled. Slice the lobster tails, 1//4-inch thick. In a mixing bowl, combine the lobster, peas, and carrots. Toss with a drizzle of truffle oil. Season with salt and pepper. Add the chervil and toss well.
To serve, unmold the mousse and place in the center of each plate. Fill the center of each mousse with the lobster salad. Garnish with parsley.