Lobster, Endive and Mango Cocktail

Description
.

Ingredients

 * 1/3 cup mayonnaise
 * 1/3 cup plain yogurt
 * 2 tbsp. cognac
 * 1 tbsp. ketchup
 * 1 tbsp. fresh lemon juice, or to taste
 * salt and pepper to taste
 * four 1 1/2-pound lobsters
 * 3 mangos, firm and ripe
 * 1 cup celery, finely diced
 * 4 whole endives, plus 12 leaves for garnish
 * 3 tbsp. minced fresh chives plus 24 whole chives for garnish

Directions
In a small bowl whisk together mayonnaise, yogurt, cognac, ketchup, lemon juice, and salt and pepper then chill covered. Plunge the lobsters into a large kettle of boiling salted water and boil them, covered, for 10 minutes. Transfer the lobsters with tongs to a bowl and let them cool until they can be handled. Crack the shells, remove the meat, and cut it into 3/4-inch pieces. Transfer the lobster meat to a large bowl and chill it, covered. The lobster cocktail may be prepared up to this point 1 day in advance. Halve the mangos by cutting just to the sides of each pit and, using a 3/4-inch melon-ball cutter, scoop the flesh from the mango halves (about 2 cups). To the lobster meat add the mango balls, celery, whole endives, trimmed and sliced thin crosswise, the minced chives and sauce, then toss mixture until combined. Divide the lobster mixture among 12 chilled small glasses and garnish each serving with 1 of the endive leaves and 2 of the whole chives.