This is the foundation for the incredible mocha dacquoise cake that Martha made to celebrate her 10th-anniversary show.
- 1 1/2 cups confectioners' sugar, plus more for dusting
- 1/3 cup Dutch-process cocoa powder
- 6 large egg whites
- 1/8 teaspoon cream of tartar
- 3/4 cup granulated sugar
Preheat oven to 250 degrees. Line 2 baking sheets with parchment paper. Using a marker, trace 12-inch circles on each sheet of parchment; turn paper marked side down. In a large bowl, sift together, confectioners' sugar and cocoa powder; set aside.
In the bowl of an electric mixer fitted with the whisk attachment, beat egg whites on medium speed until foamy. Add the cream of tartar and a tablespoon of the granulated sugar; beat until soft peaks form. With mixer running, gradually add the remaining 11 tablespoons granulated sugar, beating until stiff glossy peaks form. Fold 1/3 of the egg whites into the confectioners' sugar and cocoa mixture, then fold in remaining whites.
Transfer meringue to a large pastry bag fitted with a large plain tip. Starting just within the marked circles, pipe meringue, working inward in a spiral pattern. Bake for 2 hours. Turn off oven allowing meringues to dry out until oven is completely cool, at least 4 hours and up to overnight.