Preheat oven to 350 degrees. Using a stand mixer, beat together the butter and sugar until light in color. Add the eggs, one at a time, beating after each addition. Add the molasses.

In a mixing bowl, combine flour, baking powder, baking soda, salt, ginger, cinnamon, cloves, nutmeg, black pepper and chile powder. With the mixer on medium, add the flour mixture to the butter. Add the candied ginger and chopped nuts and mix until just combined.

Divide the dough in half and make two logs, approximately 2½ inches wide and 16 inches long. Place the logs on a parchment-lined cookie sheet, making sure they are at least 4 inches apart. Bake in the preheated oven for 25 to 30 minutes. The top of the cookie logs should be firm to the touch.

Remove cookie logs from the oven. Reduce oven to 300 degrees. Let logs cool for 20 minutes. Remove them from the parchment paper and place on a cutting board. Using a serrated knife, cut on a slight diagonal to make cookies that are approximately three-quarters of an inch wide. Place them, cut side up, on the parchment-lined pan that you baked the biscotti on. Bake for 3 minutes. Turn the cookies over and bake for another 3 minutes. Remove and cool to room temperature. If desired, drizzle melted white and dark chocolate over the cooled biscotti.