The All-American Cookie Book, by Nancy Baggett. If you love to bake cookies and do not own this book, go purchase a copy right this minute! I promise you will love it.
3 1/2 ounces unsweetened chocolate, broken up or coarsely chopped (I used Ghirardelli)
2 2/3 cups powdered sugar
2 tablespoons American-style unsweetened cocoa powder (I used Hersheys)
1/3 cup egg whites (about 3 whites) at room temperature
1 teaspoon vanilla extract
1. Preheat the oven to 325 degrees. Line several baking sheets with parchment paper.
2. In a small, microwave-safe bowl, microwave the chocolate on 100-percent power for 1 minute. Stir well. Continue microwaving on 50-percent power, stirring at 30-second intervals. Stop microwaving before the chocolate completely melts and let the residual heat finish the job. Let cool to warm.
3. In a large bowl, with an electric mixer on low speed, beat together the chocolate, about one-third of the powdered sugar and the cocoa powder until well blended. Gradually add about one-third of the egg whites and beat until evenly incorporated. Add another one-third of the powdered sugar, then another one-third of the egg whites, and beat until smooth. Repeat the process, adding the remaining one-third of the powdered sugar, then the remaining one third of the egg whites and the vanilla. Increase the speed to high and beat for 2 minutes more, or until very smooth and well blended. Let the dough stand for 5 minutes to allow the egg whites to be more fully absorbed. At this point, if the dough seems dry and crumbly, beat in 1 to 2 teaspoons water until it holds together. if the dough seems sticky and wet, beat in 1 to 2 tablespoons more powdered sugar to stiffen it just slightly. Beat the dough for 1 minute more or until very well blended.
4. Divide the dough in half. Place each portion between large sheets of wax paper. Roll out the portions a scant 1/4 inch thick; check the underside of the sough and smooth out any wrinkles that form. Working with one portion at a time, gently peel away, then pat one sheet of wax paper back into place. Flip the dough over, then peel off and discard the second sheet. Use a 2 to 2-1/4 inch heart-shaped cutter to cut out the cookies; if the cutter sticks, occasionally dip it into powdered sugar, tapping off the excess. Using a spatula, carefully transfer the cookies to the baking sheets, spacing about 1-1/4 inches apart. Reroll any dough scraps.
5. Bake the cookies, one sheet at a time, in the middle of the oven for 9 to 13 minutes, or until dry on the surface but soft in the centers when very lightly pressed. Slide the cookies, still attached to the parchment, onto a wire rack. Let stand until completely cooled. Carefully peel the cookies from the parchment.
Store in an airtight container for up to 2 days or freeze up to 1 month.