Preheat oven to 350F.
Whisk together (or sift) the flour, cocoa, espresso powder, salt, baking soda and baking powder together in a medium sized bowl and set aside.
Beat eggs lightly in mixing bowl with whisk or in an electric mixer. Beat in the sugar until just blended.
Stir in the flour mixture until the dough just comes together (don’t over mix). Fold in the nuts and chocolate chips until just combined. If the dough looks too dry, add a few drops of water to make everything come together (this may depend on your flour).
Divide the dough in half and place one portion on a lightly floured work surface (I used parchment paper and dusted it lightly with flour). Wet hands slightly, then pat the dough into a flattened log shape, about 12 inches long and 4 inches wide. Repeat with second half of dough (you can cook them side by side on a large baking sheet). I like to dollop out the dough and just flatten with my hands since the dough isn’t “rollable”.
Bake for 15-20 minutes or until firm to the touch. Remove the baked logs and let cool for about 5 minutes, then cut on an angle into 1/2 inch slices with a serrated knife. Once cut, lay the the cookies down on the cut side, then return to the oven for another 10-15 minutes or until crisp and dry.
Let cool completely. If desired, melt some chocolate for a drizzle, or dip the ends in for an even more decadent treat!