Preheat the oven to 350 degrees and line a large baking sheet with parchment paper.
In a medium bowl, whisk together the flour, cocoa powder, baking soda and salt. This is the dry mixture.
In the stand mixer bowl, cream the butter and sugar until light and fluffy, 1-2 minutes. Scrape down the sides of the bowl with a rubber spatula.
Add the eggs, one at a time, scraping down the bowl and mixing well after each addition.
Add the vanilla and mix again.
Add the dry mixture and mix until everything is combined.
On low speed, add the chocolate chips until just combined.
Dust a work surface with flour. Using a rubber spatula, scrape the sticky dough out onto the work surface. Dust the top of the dough and rub the flour on your hands. Using your hands, shape the dough into a rough ball.
Form the dough pieces into logs by rolling back and forth. Place the log onto the prepared baking sheet and shape into longer logs about 3/4-inch high and 2 inches wide.
Bake for about 30 minutes, until firm to the touch.
Let the biscotti logs cool on the pan for about 10 minutes. Move it onto a cutting board.
Using a serrated knife, slice the logs on the diagonal into 3/4-inch slices (I do this right on the baking sheet).
Place it back on the baking sheet that what use to bake the first bake, cut side up.
Bake for 10 minutes. Then flip the biscotti and bake again for 10 minutes.
Move the biscotti to wire rack and let cool and dry.
Microwave the chocolate wafer in a bowl for 30 seconds. Stir with a spoon then microwave it again for another 30 seconds. Stir to make sure everything is smooth.
Dip one end of the biscotti into the chocolate and let cool on a wax paper. Let dry before storing in an airtight container.