Preheat oven to 350 degrees F.  Line a baking sheet with parchment paper.  Set aside.

In a large bowl, using a hand-held or standing mixer, cream together the butter, sugar, salt, vanilla and baking powder until smooth.  Beat eggs in one at a time.  If the dough looks curdled, it’s okay.   Stir in flour and cinnamon until the dough is smooth.  Stir in chopped pecans until evenly combined.

Use a spatula to evenly divide dough in half.  Place dough on prepared baking sheet.  Using the spatula, and slightly wettened fingers, shape the dough into two logs about 9-1/2 inches long, 2-1/2 inches wide and about 3/4 inches thick. Smooth the sides and tops of each log.  If desired, sprinkle the dough with coarse sugar and press in gently.  Bake the dough for 25 minutes.

Remove the logs from the oven and allow to cool slightly for about 5 minutes.  Reduce the oven to 325 degrees F.  Use the serrated bread knife to slice the logs into 1/2 to 3/4 inch slices.  Be sure to cut the slices evenly (top to bottom), so the slices are an even thickness.

Use the same baking sheet to place each slice on its side.  Bake again for 25 to 30 minutes.  The biscotti will become golden brown and feel very dry.  Remove the biscotti from the oven and allow to cool on a wire rack.  The cookies will continue to dry out as they cool.   Store in a tightly sealed container for up to 7 days.