Preheat oven to 350.
Beat butter and sugar in bowl of stand mixer on speed 2 for 2 minutes.
Add eggs one at a time, beating until incorporated.
Add vanilla extract, beating until smooth.
In a separate bowl, mix flour, baking powder, and salt.
Add flour mixture to wet ingredients and mix.
Stir cherries into dough.
Divide dough in half.
Shape each half into 10″ x 4″ rectangle, using floured hands.
Set each loaf 2″ apart on a parchment lined baking sheet.
Bake for 30 minutes or until the dough is set.
Leaving the oven on, remove the biscotti loaves and cool for 15 minutes on cookie sheet.
Using a butcher's knife, cut the loaves into diagonal slices, 1/2″ thick.
Place slices on cookie sheet with the cut sides down. Bake for 8 to 9 minutes.
Turn over slices, and bake for 8 to 9 minutes more.
Remove biscotti from oven, and allow to cool completely on a cooling rack.
Combine chocolate and shortening in a small microwave-safe bowl.
Microwave for 30 seconds, then stir.
Continue heating chocolate in 15 second increments, stirring in between, until chocolate glaze is smooth.
Using a spoon, spread a layer of glaze on the top of each biscotti.
Refrigerate for 15 minutes to set glaze.