n a large bowl, cream butter and sugar.  Add eggs one at a time, beating well after each addition, beat in vanilla extract, then stir in sourdough starter.

Combine the flour, baking powder and salt. Stir in peppermint candies. Gradually add to creamed mixture, beating until blended (dough will be stiff).

Divide dough in half, on a baking sheet lined with parchment paper, roll each portion into a 12 x 2 inch rectangle. Bake at 350º for 25 to 30 minutes or until golden brown, carefully remove to wire racks.

Cool for 15 minutes. Transfer to a cutting board, cut diagonally with a serrated sharp knife into 1/2 inch slices, place cut side down on baking sheet lined with parchment paper, bake for 12 to 15 minutes or until firm.

Remove to wire racks to cool.

Make Chocolate Glaze

In a microwave proof bowl, melt chocolate chips and shortening. Stir until smooth.

Drizzle chocolate over biscotti, sprinkle with crushed peppermint candies.