Place nuts in a shallow pan and bake in a 350° F oven (or toaster oven) for 8 to 10 minutes, or until golden brown. While still warm, rub nuts between a double layer of paper towels to remove the skins. Let cool.
Preheat oven to 300° F.
In a small bowl whisk eggs, vanilla, and liquor.
In mixing bowl combine flour, sugar, cocoa, coffee powder, baking soda, and salt. Add egg mixture and mix on low until blended, about 1 minute.
Fold in the nuts by hand. Divide the dough in half.
On a floured cutting board, pat out into two logs making them about ½-inch thick, 1-½ inches wide and 12 inches long, spacing them at least 2 inches apart. Brush off any extra flour. Lay the baking sheet right next to the cutting board and carefully transfer the logs.
Bake in the middle of the 300° F preheated oven for 50 minutes or until set and baked through.
Remove from oven and reduce oven temperature to 275° F.
Using two large spatulas, one supporting either end, transfer each log from the baking sheet to the wire rack. Let cool 5 to 10 minutes. Place on the cutting board. With a serrated knife slice diagonally at a 45° angle about ½ inch thick. Insert the wire rack into the baking sheet and place the slices standing up on the wire rack. Return to the oven for 20 to 25 minutes. Remove from oven and allow to cool.
Place chopped chocolate in a microwave-safe bowl and microwave on medium for 2 minutes or until chocolate is almost completed melted with a few chunks remaining. Stir to blend. Use a spatula to spread chocolate over entire top surface of cookies. Let cool at room temperature until set. Store biscotti in a tightly covered container.