In a medium-sized mixing bowls, whisk the eggs and the sugar until they form a pale yellow, foamy mixture. Whisk in the butter, then the cocoa, whisking to incorporate each ingredient completely before the next is added. Add the liqueur and the biscotti in the same manner. When the dough becomes too thick to whisk, use a wooden spoon to mix.
Turn the dough out onto a clean work surface. Using your hands, shape the dough into a dough log 2-inches wide. Wrap the "salami" in aluminum foil and place in the refrigerator for 3 to 4 hours.
When ready to serve, remove the salami from the refrigerator. Roll log in cocoa powder and sprinkle with powdered sugar. Cut into slices and serve cold.