Preheat oven to 350°F (177°C) degrees. Line two large baking sheets with parchment paper or silicone baking mats. Set aside.

In a large mixing bowl, whisk flour, cocoa powder, brown sugar, baking powder, cinnamon and salt together. Using a pastry cutter or 2 knives, cut in the butter until the mixture is crumbly. Set aside. In a medium bowl, whisk the eggs, instant coffee mixture, oil, and vanilla together. Pour into the flour/butter mixture and gently mix with a large wooden spoon or silicone spatula until everything is just barely moistened. Fold in the chocolate chips.

Turn dough out onto a lightly floured surface, and with floured hands, knead lightly until the dough is soft and slightly sticky, about 8-10 times. If it’s uncontrollably sticky, knead 1 more Tablespoon of flour into the dough. With floured hands, divide the dough into two and place each half onto a baking sheet. Shape each half into an 8-9 inch long roll, patting down until each is about 1/2 inch thick. Using a pastry brush, lightly brush the top and sides of each biscotti slab with egg wash.

Bake in batches (or together) for 25-26 minutes, or until the top and sides of the biscotti slabs are lightly browned. Remove from the oven, but do not turn off the heat. Allow to cool for 10 minutes. Once the slabs are cool enough to handle, cut each into 1 inch thick slices. Set slices cut sides upright, 1/4 inch apart, on the baking sheets. Return to the oven to continue baking for 9 minutes. Turn biscotti over and bake other side for 9 minutes. The cookies will be slightly soft in the centers with harder edges. Remove from the oven and allow to cool for 5 minutes on the baking sheet. Then transfer to a wire rack to cool completely before dipping in chocolate. As the biscotti cools, it becomes crunchy. Save the baking sheets for the next step.

Process the chopped hazelnuts in a food processor or blender until finely chopped. Alternatively, you can chop them up into smaller pieces with a knife. Set aside. Melt the chocolate in a medium bowl in the microwave (or use a double boiler). The key to melting chocolate in the microwave is to do it in small bursts and stir frequently. Chocolate seizes so fast, so easily. Melt in 15 second increments, stirring vigorously with a spoon after each increment, until completely melted and smooth. Dip one side of each biscotti cookie in the melted chocolate and immediately sprinkle with the chopped hazelnuts. I do this over the sink to avoid a mess! Use any leftover chocolate to drizzle over the nuts. Place the dipped biscotti back onto the baking sheets and allow chocolate to set in the refrigerator or at room temperature, about 30-45 minutes.