Union Cafe's 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. Store in an airtight container at room temperature for up to three days, or freeze for up to three months.