Makes about 2 dozen cookies.
4 egg whites, at room temperature
⅛ teaspoon cream of tartar
Pinch of salt
1 cup superfine sugar
2 tablespoons unsweetened cocoa powder, sifted or whisked to remove lumps
3 ounces dark chocolate
⅓ cup heavy cream
¼ cup packed brown sugar
1 tablespoon balsamic vinegar
2 tablespoons cold butter
1 teaspoon vanilla extract
To prepare cookies: Preheat oven to 250 degrees and line baking sheets with parchment paper.
In a bowl of an electric mixer fitted with a whisk attachment on medium-high speed, beat egg whites, cream of tartar and salt until mixture is foamy. Gradually add sugar and continue beating until egg whites are very stiff and form solid peaks when the whisk is lifted out of the bowl, at least 5 minutes. Using a rubber spatula, carefully fold in cocoa powder.
Using a pastry bag fitted with a star tip (or a plastic bag, with a corner cut out), fill bag with batter and pipe a basket-shaped circular cookie, 1½ -inches wide and 1½ -inches tall, with a small indented opening in the center (or make a tiny depression in top of cookie with wet finger or back of wet spoon). You could also use a small scoop to drop mounds of batter onto prepared baking sheets and make the indentation on top separately. Repeat with remaining batter.
Bake until cookies are dry and crisp on the outside but tender on the inside, 50 to 60 minutes. If cookies start to take on any color, reduce heat to 200 degrees. Remove from oven and cool 5 minutes before transferring cookies to a wire rack to cool completely.
To prepare sauce: In small saucepan over low heat, combine chocolate, cream and brown sugar, stirring occasionally until chocolate has melted. Stir in vinegar. Remove from heat, stir in butter until melted. Stir in vanilla extract and cool slightly. Spoon sauce into center of cookies.
2012 Winner: Patrice Johnson of Roseville, Minnesota