Preheat oven to 350 degrees.
Lightly grease a cookie sheet or line with parchment paper. Set aside.
Place 3/4 cup of toasted almonds in a food processor and pulse until ground.
Beat butter in large bowl for 30 seconds, then add sugar, cocoa, baking powder, baking soda and salt; beat until combined.
Beat in eggs and almond extract.
Beat in as much of the flour as you can with mixer.
By hand, stir in remaining flour, the ground almonds and the remaining 3/4 cup of sliced almonds.
On pieces of wax paper, shape dough into two 14 inch long rolls.
Place rolls on prepared cookie sheet at least 5 inches apart, flatten slightly.
Bake 25-30 minutes or until wooden pick inserted near centers comes out clean.
Cool on cookie sheet for 1 hour.
Cut each roll diagonally into 1/2 inch thick slices.
Place slices, cut sides down, on ungreased cookie sheets (or cookie sheets that have been lined with parchment paper).
Bake 8 minutes.
Turn slices; bake 7 to 9 minutes more or until cookies are dry and begin to crisp (do not overbake).
Remove from cookie sheets to wire racks.
If desired, to make glaze or drizzle, place semi sweet chips and white chips in separate small microwave safe bowls.
Add 1 teaspoon of shortening to each bowl.
Microwave on high for 45 seconds, stirring once; stir. If necessary, microwave an additional 15 seconds or until chips are melted and mixtures are smooth when stirred.
Dip biscotti into mixtures or drizzle over tops.