01 - Preheat the oven to 350°F. Line a baking sheet with parchment paper.
02 - Whisk together flour, ground ginger, cinnamon, cloves, nutmeg, baking powder, baking soda, and salt in a medium bowl.
03 - In a large bowl, beat unsalted butter and brown sugar until light and fluffy.
04 - Add eggs one at a time to butter mixture, then mix in molasses and vanilla extract.
05 - Dissolve instant espresso powder in 1 tablespoon hot water and add to wet ingredients.
06 - Gradually add dry ingredients to wet ingredients, stirring until just combined.
07 - Gently fold in chopped almonds (if using) and crystallized ginger.
08 - Divide dough in half and shape each portion into a 12-inch long, 2-inch wide log on prepared baking sheet.
09 - Bake logs at 350°F for 25 minutes until firm and lightly browned. Remove and cool for 10 minutes.
10 - Reduce oven temperature to 300°F.
11 - Using a serrated knife, cut logs diagonally into 1/2-inch thick slices and place cut side down on baking sheet.
12 - Bake slices for 15 to 20 minutes, turning once halfway through, until crisp and golden.
13 - Transfer biscotti to a wire rack and cool completely before serving.