Ingredients
1 cup all-purpose flour
3 tablespoons Dutch-process cocoa powder
1/2 cup unsalted butter, at room temperature
2/3 cup confectioner's sugar
4 large egg whites, at room temperature
Preparation
Sift flour with cocoa, and set aside.
In the bowl of an electric mixer fitted with the paddle attachment, beat butter and sugar on medium until well-combined, about 2 minutes. Beat in egg whites, one at a time, beating for 4 minutes after each addition. Add the flour-and-cocoa mixture, and mix until just combined.
Reserve 1/2 cup batter; place in a pastry bag fitted with a #2 tip, and set aside for piping white tuile cookies.
