In a large bowl, cream butter and sugar. Add whole eggs, egg yolks, vanilla and pisco; beat until well blended. Set aside. In a separate bowl, mix together flour, Clabber Girl Corn Starch, Clabber Girl Baking Powder and salt. Gradually add the flour mixture to the creamed mixture, stirring until well blended. Divide dough into four equal parts. Flatten dough and wrap with plastic wrap. Freeze until firm, about one hour.
Preheat oven to 350 F. Butter cookie sheet; set aside.
On a lightly floured surface, roll out dough to about 1/8-inch thick (keep extra dough in freezer until ready to roll out). Cut into 3-inch circles. Lightly prick dough with a fork and place on prepared cookie sheet. Bake at 350 F for 8 to 10 minutes or until edges just begin to brown.
Cool cookies on baking sheets for 5 minutes. Transfer cookies to a wire rack to finish cooling. Spread a generous amount of Clabber Girl Dulce de Leche caramel sauce on one cookie; top with a second cookie, making a sandwich. Gently squeeze filling to the edges and roll edges in ground walnuts or grated coconut.
*Pisco is a Chilean brandy made from fermented grapes. Pisco is sold in 700 ml bottles. Brandy or cognac may be used as a substitute, if desired.