Chocolate Pinwheel Cookies

Instructions

1. In a medium bowl, mix together the flour, salt, and baking soda. Set aside.
2. Break the chocolate into 1-inch pieces. Melt in the top of a double boiler or in a heatproof bowl, over barely simmering water, stirring occasionally until smooth. Set aside.
3. Using an electric mixer on medium speed, cream butter until smooth, about 2 minutes. Mix in the sugar and beat for an additional 2 minutes. Add the egg and vanilla, mixing well until combined. Reduce the speed to LOW and add the flour mixture slowing, mixing until just incorporated.
4. Separate out 2 cups of the dough and set aside.
5. Dissolve the espresso powder in the boiling water and set aside to cool. Once cool, mix the espresso and cocoa into the remaining dough until the dough is evenly colored. On low speed, add in the melted chocolate, mixing until thoroughly combined.
6. Divide each flavor of dough (vanilla and chocolate) into three equal pieced. On pieces of plastic wrap, shape each piece of dough into a 5" square and wrap well.
7. Chill the dough for at least 30 minutes in the refrigerator.
8. While the dough is chilling, tear off twelve 10-inch squares of parchment paper. Roll each piece of chilled dough into thinner 7" squares between two pieces of parchment paper. Without removing the parchment paper, layer the dough on a baking sheet and chill in the refrigerator for 15 minutes.
9. To form the pinwheels, invert the vanilla squares on top of the chocolate square (peel off the top papers first). Trim the edges and roll gently to seel. Peel off the top layer of parchment paper. Starting from the nearest edge, roll the dough tightly into a cylinder, using the bottom parchment for leverage. After you form the cylinder, roll it gently back and forth. Put the elongated cylinder on the OXO Slice & Bake Cookie Helper mat. Roll it tightly to 2", pull the strap to secure. Refrigerate for 3 hours, and repeat the above procedure with the remaining four pieces of dough.
10. Preheat the oven to 350ºF. Line cookie sheets with parchment paper.
11. Slice into ¼-inch rounds and place 1 inch apart on the prepared baking sheet.
12. Bake for 12 minutes, making sure not to brown the edges too much. Remove the cookies from the oven, and let stand for 1 minute.
13. Transfer to wire racks and let cool completely. Store in an airtight container at room temperature for up to a week.