Chef John's Gingerbread Biscotti

Instructions

• Whisk flour, baking powder, salt, ground ginger, cinnamon, nutmeg, and cayenne together in a bowl until thoroughly combined.
• Combine butter, brown sugar, and molasses in a bowl; mix with a spatula until creamy. Whisk in eggs, one at a time, until smooth. Add vanilla and chopped ginger. Mix and mash with the whisk until ginger is evenly distributed and coated with the butter-sugar mixture, about 1 minute.
• Mix in 1/2 of the dry ingredients with a spatula until incorporated. Mix in remaining dry ingredients until dough is very wet and sticky.
• Transfer dough to a long piece of plastic wrap, using a buttered knife to help if necessary. Wrap plastic around the dough and shape with your hands into a uniform log, about 12 to 14 inches long by 2 1/2 inches wide. Place in the refrigerator to chill for at least 30 minutes.
• Preheat the oven to 350 degrees F (175 degrees C). Line a baking sheet with a silicone baking mat.
• Remove dough from the refrigerator, unwrap, and place on the prepared baking sheet. Wet your fingers and smooth out any edges.
• Bake in the center of the preheated oven until a toothpick inserted into the center comes out clean, about 30 minutes.
• Remove loaf from the oven, cover with a clean towel, and let sit for 20 minutes. Reduce oven temperature to 325 degrees F (165 degrees C).
• Uncover the loaf and brush a little water around the bottom edge to soften. Transfer to a cutting board.
• Use a serrated knife to cut the loaf into 1/2-inch slices. Cut at an angle for longer biscotti, or straight across for shorter ones. Transfer slices back to the baking sheet.
• Return to the oven and bake for 20 minutes. Flip biscotti and cook until they are dry and crispy all the way through, 10 to 15 minutes longer. Transfer to a cooling rack and let cool to room temperature.
• Place melted white chocolate into a plastic bag. Snip off a corner and pipe over biscotti. Let sit until chocolate has cooled and hardened, about 30 minutes.