Whisk flour, baking powder and salt in a medium bowl to blend.

Set aside.

Using an electric mixer, beat sugar and butter in a large bowl to blend.

Beat in eggs 1 at a time, then liqueur and orange peel.

Add flour mixture and beat until blended.

Stir in pecans and chocolate.

Gather dough together and divide in half.

Wrap each piece in plastic and freeze until firm, about 20 minutes.

Line a large baking sheet with parchment paper.

Position rack in center of oven.

Preheat oven to 350°F.

Using floured hands, form each dough piece into a 14 inch long, 2 1/2 inch wide log.

Transfer logs to prepared baking sheet, spacing 2 inches apart.

Bake until lightly golden, about 30 minutes.

Transfer parchment paper with logs to a cooling rack.

Cool for 20 minutes.

Reduce oven temperature to 300°F.

Place 1 log on a cutting board.

Using a serrated knife, cut log on a diagonal into 1/2 inch thick slices.

Stand slices upright on a baking sheet.

Repeat with remaining log.

Bake biscotti until dry to the touch and pale golden, about 30 minutes.

Cool completely on a rack.

*This can be made 1 week ahead. Store in an airtight container.*

**This recipe makes about 36 biscotti.**