Toast the almonds on a baking sheet in the oven at 350F (180C) for about 15 minutes. Shake the pan once to make sure they get evenly browned.
Cream butter, sugar, and vanilla together in a large bowl with an electric mixer until light and fluffy. Add eggs and then cocoa. Beat until well combined.
Sift the flour, baking powder and salt together in another bowl, then gradually incorporate into the wet ingredients with a wooden spoon until a dough has formed.
Stir in the chocolate chips and almonds. Cover the bowl with plastic wrap and chill for an hour.
Preheat oven to 325F (160C). Turn dough out onto a lightly floured board. Separate into two. Form each half into a flat log about 12 inches long by patting it down and squaring off the edges with your finger tips. Place well apart on a baking sheet lined with parchment paper.
Bake for thirty mintues. Cool on a cutting board until no longer hot to the touch and then cut crosswise on the diagonal into slices about 1 inch thick. Arrange on the baking sheet and bake for another 15-20 minutes.
Transfer biscotti on a wire rack to cool. Keep at room temperature in a cookie tin or other airtight container.