Preheat oven to 325 degrees. In a medium bowl combine flour, cornstarch, baking powder and salt.

In a mixer fitted with a paddle attachment, add butter and powdered sugar and beat until light and silky. Beat in eggs one at a time. Batter will not fully combine. Then add extracts and zest.

On low speed, add flour mixture slowly and beat until fully combined. On a cookies sheet lined with parchment paper or spray with cooking spray, drop dough by teaspoonfuls rolled into balls. Then take a floured fork and make a criss cross design on top of each ball. Bake for 20 minutes. Let cool on cooling rack.

In a glass bowl melt chocolate in microwave. Dip half of each cookie in melted chocolate and place on parchment paper or silpat to cool.