Step 1

Process cookies into fine crumbs in a food processor, about 45 seconds; you will need 1 cup crumbs. Line a 2-quart straight-sided plastic pitcher with plastic wrap, leaving a 6-inch overhang; chill in freezer. Let sorbets soften slightly in refrigerator.

Step 2

Layer sorbets into pitcher 1 pint at a time, pressing down with a ladle. Smooth each layer with a rubber spatula, and sprinkle with 1/4-cup cookie crumbs. Continue layering until pitcher is full. Cover; freeze overnight.

Step 3

Remove pitcher from freezer. Briefly run warm water over outside of pitcher to loosen sorbet. Using edges of plastic wrap, lift sorbet out of the pitcher; invert molded sorbet onto a freezer-safe serving platter, and remove the plastic wrap. Return to freezer.

Step 4

Combine sugar and 1/2 cup water in a small saucepan, stirring gently with a metal spoon. Cover, and cook over medium-high heat until sugar dissolves, 5 to 6 minutes. Uncover, and place a candy thermometer in syrup. Raise heat to high; boil rapidly until temperature reaches 248 degrees.(firm-ball stage), 1 to 2 minutes.

Step 5

While sugar is heating, beat egg whites in bowl of an electric mixer with whisk attachment at low speed until foamy, about 2 minutes. Gradually increase speed to medium high, and beat until soft peaks begin to form, 2 to 2 1/2 minutes. Reduce speed to low, and add hot syrup in a steady stream. Increase speed to medium high, and continue beating until whites are shiny, stiff, and hold a peak, about 2 minutes. Do not overbeat. Increase speed to high, add vanilla, and beat for 15 seconds more. Transfer to another bowl, and let cool for about 5 minutes, folding gently 1 or 2 times.

Step 6

Remove sorbet from freezer. Working quickly, cover entire surface with meringue. Freeze for at least 1 hour and up to 1 day.

Step 7

When ready to serve dessert, place strips of aluminum foil around base of sorbet to protect serving platter. Using a kitchen torch, brown meringue all over. Remove aluminum strips, and drizzle blue curacao around base, if desired.