Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.
In a medium bowl, whisk together the all-purpose flour, cocoa powder, instant espresso powder, baking soda, baking powder, and salt until no lumps remain. Set aside.
In a large mixing bowl, cream the room temperature butter and sugar together until light and fluffy, about 2-3 minutes.
Add the lightly beaten eggs and vanilla extract to the butter-sugar mixture and mix until well combined.
Gradually add the dry ingredient mixture to the wet ingredients, mixing until just combined. Do not overmix.
Gently fold in the chopped bittersweet chocolate and almonds (or white chocolate) using a rubber spatula. The dough will be thick and slightly sticky.
Divide the dough in half and shape each half into a log about 12 inches long and 3 inches wide on the prepared baking sheet, leaving space between the logs.
Bake in the preheated oven for 25-30 minutes, until the logs are firm and slightly cracked on top. Remove and let cool for about 10 minutes.
Using a sharp knife, slice the logs diagonally into ¾-inch thick pieces. Arrange the slices cut side down back on the baking sheet.
Bake the biscotti again for 15-20 minutes until firm and dry. Watch closely to avoid burning.
Remove from oven and cool on a wire rack. Once cool, dust with sugar for a sweet finishing touch.