Ingredients
1 cup all purpose flour
1/4 tsp. baking powder
1/8 tsp. salt
1 oz semi-sweet chocolate, chopped
1/2 cup sugar
1 large egg, separated
1 tsp. vanilla extract
1 tsp. grated orange zest
2 tsp. cocoa powder
~ In a bowl sift together the flour, baking powder, and salt. Set aside. Place the chocolate in the top of a double boiler placed over (not touching) barely simmering water. Heat, stirring often, until the chocolate melts. Remove from over the water and set aside to cool slightly
~ In a large bowl, combine the butter and sugar. Beat with a wooden spoon until smooth, about 3 minutes. Add the egg yolk and vanilla and beat until blended. Add the dry ingredients and mix until incorporated and the dough is smooth
~ Divide the dough in half. Put one-half of the dough in a separate bowl and stir in the orange zest. Add the melted chocolate and cocoa powder to the dough remaining in the large bowl and mix on low speed or with a wooden spoon until blended completely into the dough. gather up each portion of dough, form each into a 5 inch (13 cm) square, and wrap separately in plastic wrap. Refrigerate until firm, about 45 minutes.
~ Remove the dough from the refrigerator. One at a time, place each dough portion between 2 sheets of waxed paper and roll out into a rectangle 10 by 5 inches and about 1/8 inch thick. Remove the top piece of waxed paper from each rectangle. In a small bowl, using a fork, beat the egg white until foamy. Brush it lightly over the top surface of the chocolate dough. Using the waxed paper, flip the chocolate dough onto the orange dough and press the doughs together. Peel off and discard the top piece of waxed paper. Trim the dough edges evenly. Roll up the 2 layers of dough into a tight log, removing the remaining piece of waxed paper as you roll. gently press the seam along the length of the roll to seal it. Trim the end evenly. The roll should be about 9 inches long. Wrap in plastic wrap and refrigerate until firm, at least 1 hour or overnight.
~Position a rack in the middle of the oven, and preheat to 350'F(180'C). Line 2 rimless baking sheets with parchment paper. Unwrap the pinwheel log on a cutting board. using a large, sharp knife, cut the dough crosswise into slices 1/4 inch thick. Place them 1 inch apart on the prepared baking sheets
~ Bake the cookies, 1 sheet at a time, until the edges just begin to turn lightly golden, 8-12 minutes. Let the cookies cool on the baking sheets for 5 minutes, then transfer them to wire racks to cool completely. Store in an airtight container at room temperature for up to 5 days
ENJOY! :) (man those instructions took forever @.@)
recipe from Williams- Sonoma's Essentials of Baking