Preheat oven to 325º F. Line a baking sheet with parchment

Put ⅔ cup of the chocolate morsels in a microwave-safe bowl and heat on high for 45 seconds. Stir well, then continue microwaving and stirring every 30 seconds until smooth.

Mix the flour, baking powder and salt in small bowl. Set aside.

With an electric mixer, Beat sugar and butter in large bowl until light and fluffy. Add eggs and extract and beat until combined. Stir in melted chocolate. Gradually stir in flour mixture, then stir in nuts and the ⅔ cup of espresso morsels.

With slightly damp hands, shape dough into a 12 x 3-inch log with a rounded top, directly on the baking sheet.

Bake the log at 325 for 40 minutes or until slightly firm to the touch and cracked on top. Let cool on baking sheet for 10 minutes, then slide log onto cutting board and cut into 18 even slices. Return to baking sheet and stand the biscotti on the sheet. If you prefer, you can lay the pieces on their side.

Reduce heat to 300 degrees F. and bake for an additional 20 to 25 minutes. Remove to wire rack to cool completely. It will crisp as it cools.

Put the remaining chocolate (either semisweet morsels or espresso morsels) in a freezer bag and microwave for 30 seconds. Massage bag to help melt the chips, and push the chips toward the bottom corner. Microwave for 10 seconds. Cut a tiny corner from bag and drizzle over cooled biscotti. Let stand until drizzle is set. Store in airtight container at room temperature.