Merveillux

Preparation

1. Step 1

   Preheat the oven to 275°F (135°C). Cut a sheet of parchment paper large enough to line a large rimmed baking sheet, and place dull side up on a work surface. Place a circular object the size of a 45 rpm record on one end of the paper, and trace the outer edge with a pencil. Repeat twice more on the other end of the paper. Flip the paper over and put it on a baking sheet.

   Step 2

   To make the meringue, in a stand mixer fitted with the whip attachment, whip the egg whites and vinegar on high speed until stiff peaks form, adding the sugar in three shots, the beginning, the middle, and toward the end. The whole process should take about 6 minutes.

   Step 3

   Spoon the whites mixture into a pastry bag fitted with a round, plain tip (an Ateco no. 807, about 1/2 inch/ 12 mm in diameter, is ideal). First, pipe a tiny dab under each corner of the parchment to hold it in place while you pipe the disks. They will also prevent a fly out if you use a convection oven (imagine those old game shows where contestants had to grab money blowing around inside an air tube and you’ll understand). Now, pipe the meringue onto one of the parchment templates in a spiral design, starting just inside the traced line and working toward the center in a continuous motion. Repeat on the two additional templates to make a total of three disks. If you have a little room and a little meringue left, make little dots here and there.

   Step 4

   Bake for 30 minutes, then lower the oven temperature to 225°F (110°C) and continue to bake for another 2 hours, keeping the oven door ajar, if possible (a pair of metal tongs sometimes works). The meringues are ready when they are light beige and the surface is crisp but the middle is still soft.

   Step 5

   Let the meringues cool on the pan before transferring them to a wire rack or a large platter. Don’t worry if they break. They will be covered with cream and sauce.

   Step 6

   To make the cream, in a bowl, by hand or with a mixer, whip the cream, gradually adding the sugar and rum, until stiff peaks form. Be careful to stop before it turns into butter. Using a rubber spatula, fold in the chocolate, distributing it evenly.

   Step 7

   Put a little blotch of the cream on the center of a serving plate, and place a meringue disk on top (the cream will anchor it). Spread one-third of the chocolate cream evenly over the disk and place the second disk on top. Cover with another one-third of the cream and place the third disk on top. Cover with the remaining cream, press the disks together slightly so the cream squishes out the sides. With a clean spatula, smooth the cream over the top and sides.

   Step 8

   Finely grate the chocolate for the topping and blow it all over the cake. Cover and refrigerate for 1 hour before serving. (While you are waiting, you can munch on any little meringues that rode along with the big disks.)

   Step 9

   Just before serving the meringue, make the chocolate sauce. To cut the meringue, dip a serrated knife blade in cold water before each cut, and wipe clean after each cut. Pass the hot chocolate sauce at the table.