Cookery Art - Chocolate meringue "sandwiches"

To make the meringues, heat the oven to 250 degrees F.
Draw 20 circles, 2 inches in diameter, 1 inch apart, on a piece of parchment paper. Put the paper in the baking pan, marked side down.
Sift the powdered sugar with the cocoa.
Put the egg whites in the bowl of a heavy-duty mixer. Beat the whites with the whisk attachment, starting on medium speed. When they start to froth, add about a third of the granulated sugar and beat until they become opaque and increase in volume. Add another third of the sugar, and beat until they start to become firm. Then turn up the mixer speed, add the rest of the sugar and beat until they are stiff but still glossy. The whites will hang in soft, droopy peaks from the whisk when it is lifted from the bowl.
Remove the bowl from the mixer. Sift a third of the powdered sugar and cocoa over the bowl (this will be the second time it is sifted), and fold this into the whites. Use a rubber spatula to fold, going to the bottom of the bowl in the center and coming up along the side. Rotate the bowl slightly after every fold. Fold in the remaining powdered sugar in two stages, sifting it into the bowl each time.
Fit a pastry bag with a plain 3/8-inch tip, and fill it with the meringue. Starting in the center of each circle, pipe a coil, filling the circles.
Bake the meringues on the middle shelf of the oven until they are firm and can be detached from the paper, about one hour. Cool the baking pan on a rack. When the meringues are completely cool, store them in an airtight container at room temperature.
To make the filling, bring the whipping cream to a boil in a medium saucepan. Remove it from the heat. Add the chopped chocolate, and let it sit for five minutes. Whisk the chocolate into the cream until it is smooth. Transfer the chocolate cream to a bowl, cover it and refrigerate.
The filling should be the consistency of thick mayonnaise. If it is freshly made, cool it until it thickens. If made ahead, leave it at room temperature until it softens.
To assemble the desserts, pile a generous tablespoon of filling in the middle of eight meringues. Gently place another meringue on top of each, being careful not to push down too hard, so that each sandwich maintains some height. Put the meringues in the freezer for 20 minutes.
Crush the remaining meringues between pieces of wax or parchment paper. Remove the filled meringues from the freezer. Using a small offset spatula or a kitchen knife, smooth the remaining filling onto the sides of the sandwiches. Roll each finished sandwich in the crushed meringues.
Refrigerate the desserts until 30 minutes before serving.
Note: The components can be made ahead. Store the meringues, airtight, for up to two weeks, and the filling, refrigerated, for up to five days. Let the assembled desserts sit at room temperature for 30 minutes before serving, so the filling softens.