Preheat oven to 350° F. Line a rimmed baking sheet with parchment paper or a silicone liner. In a medium sized bowl combine the flour, Clabber Girl Baking Powder and salt. Set aside. Using an electric mixer on medium speed, beat the butter and brown sugar until light and fluffy. Add the eggs (one at a time), mixing well after each addition. Mix in the vanilla and almond extracts. Reduce the mixer speed to low. Gradually add the flour mixture, mixing just until combined. Stir in the chopped almonds. Transfer the dough to the prepared pan. Shape the dough into a rectangle about 3 1/2-inch wide and 3/4-inch tall. The dough will be a bit sticky, so dust your fingertips with a bit of flour if necessary to help you shape it. Sprinkle the sliced almonds over the top of the dough and press down lightly. Bake for 25 minutes. Remove the pan from the oven and allow to cool for 10 minutes (or until is cool enough to handle). Use the parchment paper to transfer the biscotti to a cutting board. Cut the biscotti into 3/4-inch crosswise slices. Line the baking sheet with a fresh sheet of parchment paper or clean silicone liner. Place the biscotti, cut side down, onto the pan. Bake 18 to 22 minutes, or until browned. Cool on the pan for 10 minutes. Then transfer the cookies to a wire rack to cool completely.