Chocolate Biscotti

Notes: Preheat oven to 350 degrees. Line a 12- by 17-inch baking sheet with parchment paper or nonstick liner. Sift together the flour, cocoa, salt and baking soda; set aside. Using a heavy-duty electric mixer, cream together the brown sugar, granulated sugar and butter for 3 to 5 minutes at medium speed. Add vanilla extract and espresso. Mix for 10 seconds. Add eggs one at a time, mixing for 10 seconds at medium-low speed after each addition. Add sifted flour mixture and mix at low speed until dough comes together, 1 to 2 minutes. Add chocolate chips and mix just until chips are evenly incorporated, 15 to 20 seconds. Transfer dough to a work surface and divide in two, shaping into balls. Form each ball into a log 1 1/2 to 2 inches wide. Transfer logs to prepared baking sheet and flatten slightly. Brush tops of logs with egg wash and sprinkle each log with 1 tablespoon raw sugar. Bake until biscotti have spread, have a few cracks and bounce back slightly when pressed with fingertips, 30 to 40 minutes. Remove from oven and let cool completely, about 1 1/2 hours. Preheat oven to 325 degrees. Using a sharp serrated knife, cut logs into 1/4-inch to 1/2-inch slices. Place each slice with a cut side down on a baking sheet lined with parchment paper or nonstick liner. Bake until firm, crisp and slightly dry, about 15 minutes.