Preheat oven to 350 degrees F (180 degrees C).  Toast almonds for 8-10 minutes or until lightly browned and fragrant.  Let cool and then chop coarsely.  Set aside.

Line a baking sheet with parchment paper.  Set aside.

In bowl of your electric mixer (or with a hand mixer), beat the sugar and eggs on high speed until thick, pale, and fluffy (about 5 minutes).  (When you slowly raise the beaters the batter will fall back into the bowl in slow ribbons.)  At this point beat in the vanilla extract.   In a separate bowl, whisk together the flour, baking powder and salt.  Add to the egg mixture and beat until combined.  Fold in the chopped almonds and chocolate.

Transfer the dough to your parchment lined baking sheet and form into a log, about 12 inches (30 cm) long and 3 1/2 inches (9 cm) wide.  You may have to dampen your hands to form the log as the dough is quite sticky.  Bake for 25 minutes, or until firm to the touch.  Remove from oven and let cool on a wire rack for about 10 minutes. 

Reduce oven temperature to 325 degrees F (165 degrees C).  Transfer the log to a cutting board and cut into 3/4 inch (2 cm) slices, on the diagonal.  Place the biscotti, cut side down, on the baking sheet.  Bake for about 10 minutes, turn slices over, and bake for another 10 minutes or until golden brown.  Remove from oven and let cool.  Store in an airtight container.

Makes about 16 biscotti.

Adapted from David Lebovitz's 'Room for Dessert.'