1. Preheat oven to 325°. Pulse mini-morsels in a food processor 10 times or until morsels are almost ground. Remove to a bowl. Add flour, powdered sugar, cornstarch, and butter to food processor. Cover; process just until a dough forms and mixture holds its shape. Stir in 1/4 cup hazelnuts and ground mini-morsels. Turn dough out onto a lightly floured surface. Roll dough to about 1/2-inch thickness; cut with a 2-inch scallop-shaped cutter. Press remaining 1/4 cup hazelnuts into top of each cookie. Place 1 inch apart on parchment paper-lined baking sheets.
2. Bake at 325° for 18 to 20 minutes or until golden brown. Cool on baking sheets 5 minutes; transfer to wire racks, and cool completely (about 30 minutes).