Preheat the oven to 350 degrees F. Line a large baking sheet with parchment paper.
In a medium bowl, whisk together flour, cocoa powder, baking powder, and kosher salt. Set aside.
1 3/4 cup All-purpose flour, 1 1/4 tsp Baking powder, 1/2 tsp Kosher salt, 1/2 cup Unsweetened cocoa powder
In a large bowl, using an electric mixer, beat together butter, granulated sugar, and dark brown sugar until light and fluffy (about 3 minutes). Add eggs and peppermint extract, and beat until combined well. Add the dry ingredients and mix just until a stiff dough is formed. Fold in the mini chocolate chips.
1/2 cup Unsalted butter, 1/2 cup Granulated sugar, 1/2 cup Dark brown sugar, 2 large Eggs, 1 tsp Peppermint extract, 3/4 cup Mini semi-sweet chocolate chips
Divide the dough in half, with slightly damp fingers, and form two 10-inch x 2-inch logs on the prepared baking sheet. Bake for 25-30 minutes, until the top and edges are set. Cool on the baking sheet for 5-10 minutes. Reduce oven temp to 325ºF.
Transfer to a cutting board and cut diagonally into 3/4-inch wide slices. Place them back on the baking pan standing up with 1/2 inch in between each one. Bake for another 20-25 minutes, until dry. Transfer to a wire rack to cool completely.
Melt the white chocolate according to the package instructions. Drizzle with melted white chocolate and sprinkle the crushed peppermint. Or you can dip one side of each biscotti in the melted chocolate and sprinkle.
4 ounces White chocolate chips, 3 tbsp Crushed peppermint candy