Step 1Line a baking sheet with parchment and set aside.
Step 2In a bowl, sift together the flour, baking powder and salt and set aside. In a separate bowl, whisk together the espresso powder, dark cocoa powder and Dutch process cocoa powder and set aside.
Step 3In the work bowl of a stand mixer, combine the butter, sugar and brown sugar and beat at medium-high speed until fully incorporated and light and creamy, 3 to 5 minutes. Slowly add 2 of the eggs, the vanilla and almond extract. Mix well and scrape down the sides of the bowl well. Add the espresso-cocoa powder mixture and mix and scrape well. Add the flour mixture and mix and scrape until no white streaks are present. Add the candied orange peel, chocolate and hazelnuts to form a dough.
Step 4Turn the dough onto the prepared baking sheet and form the dough into a half cylinder log about 12 inches long, 3 3/4 inches wide at the base and 1 1/2 inches tall.
Step 5Freeze the log overnight.
Step 6Heat the oven to 325 degrees.
Step 7Separate the remaining egg, whisk the white and brush it onto the frozen log (reserve the yolk for another use). Sprinkle sugar on top of the log and bake until slightly firm in the center, taking care not to overbake as the dough is dark so color is not a good indicator, about 1 hour.
Step 8Cool completely, about 2 hours.
Step 9Cut the log crosswise into 3/4” thick slices. Place each slice on its side and bake until firm to the touch, taking care not to overbake, about 30 minutes.