Crisp chocolate biscotti cookies dipped with dark chocolate and finished with flaky salt. These traditional Italian "twice-baked" cookies will turn even the biggest skeptics into biscotti lovers!
Preheat the oven to 350°F (176°C) with a rack in the center position. Line a half sheet pan with parchment paper and set aside.
Combine the flour, cocoa powder, espresso powder, baking soda, baking powder, and salt in a medium bowl, whisk together, and set aside.
In the bowl of stand mixer, fitted with a paddle attachment, combine the butter and sugar. Beat over medium speed for 2 to 3 minutes, or until the mixture is fluffy and pale in color. Add the eggs and vanilla and continue to beat for 1 to 2 minutes, scraping down the bowl with a spatula to ensure all of the ingredients incorporate evenly.
Reduce speed to low and slowly add the dry flour mixture, mixing until a dough just comes together. Add the almonds and mix until just incorporated. The dough will be thick and fairly sticky.
Turn the dough onto a clean counter top and knead the dough lightly to combine any dry ingredients that were not incorporated. Divide the dough in half using a bench scraper. Roll each piece into a 12-inch (30 cm) log and set on the lined sheet pan, leaving space between them for spreading. Flatten the logs with your palm, until they are ¾-inch to 1-inch (2 cm - 2.5 cm) thick and rectangular in shape. Sprinkle the tops of the logs with granulated sugar.
Bake for 25 minutes or until the logs are firm to the touch. Set the pan on a rack and allow the logs to cool on the baking sheet for 20 minutes. Leave the oven preheated.
Remove the logs to a cutting board, and using a serrated knife, cut each log cross-wise into ½ to ¾-inch thick pieces. Set the cookies, cut-side down, onto the lined half sheet pan. The pieces can be placed close together, as they will not spread during this second baking.
Bake at 350°F (176°C) for 10 minutes or until crisp. Transfer the biscotti to a wire rack to cool completely.
Decorate: Once cookies are cool, melt the chocolate in a microwave-safe bowl in 15 to 20 second increments, stirring with a spatula between each interval. Dip the cookies lengthwise into the melted chocolate, coating half-way up the edge.
Lay the biscotti on the parchment lined baking sheet. Allow the chocolate to set a bit before sprinkling with flaky salt. If using glazing chocolate, the chocolate should set fairly quickly. If not, feel free to place them in the refrigerator for 5 to 10 minutes or until the chocolate is firm. Biscotti can be kept in an airtight container for up to 1 week or longer.