Preheat oven to 350 degrees F. Line large baking pan with parchment paper.
Whisk flour and baking powder in a bowl. Using a mixer, beat sugar, butter, lemon zest, and salt to blend. Beat in eggs one at a time. Add the flour mixture and beat until blended. Stir in pistachios and cranberries.
From dough into 13"x3" log on the prepared baking sheet. Bake in overn for 40 minutes or until golden. Cool for 30 minuites.
Place log on cutting board. Using a serrated knife, cut log on a diagonal line into 1/2-3/4" thick slices. Arrange biscotti cutside down on baking sheet. Bake additional 20 minutes.
Stir chocolate in a bowl set over a saucepan of simmering water until melted. Dip half of biscotti into melted chocolate. Shake excess off gently then place on cookie sheet. Sprinkle with whatever extra you want and then refrigerate :)