Mini chocolate chips add to the buttery richness of shortbread. Additional chips are melted and drizzled over the baked cookies.
Heat oven to 325 degrees F. Stir together flour and cornstarch in small bowl.
With mixer on medium-high speed, beat butter in large bowl until smooth and creamy. Add confectioners sugar, granulated sugar and salt; beat until very light colored and fluffy, 3 to 5 minutes.
On low speed, slowly sift flour mixture over butter mixture, beating until dough forms. Dough will be stiff and may separate, looking like coarse meal.
Transfer dough to lightly floured surface. Add 1 cup mini-chips; knead by hand until chips are evenly distributed.
Divide dough in half. Add extra flour to board. Press each half into 8-inch circle. Carefully transfer to ungreased baking sheet. Using sharp knife, divide each circle into 8 wedges, slicing completely through dough. Prick dough with tines of fork. Flute edges if desired.
Bake in 325 degrees F oven 25 minutes or until lightly golden. Immediately separate into wedges. Remove wedges to wire rack to cool.
Melt remaining chips in saucepan. Pour into plastic bag; snip corner; drizzle over shortbread. Makes 16 shortbreads.