Don't skip the chill time after mixing or the dough will be too soft to shape into a log.
Combine flour and cornmeal. Beat butter and sugar at medium speed with an electric mixer until light and fluffy. Add egg and next 3 ingredients, beating until blended. Gradually add flour mixture, beating just until blended after each addition. Cover and chill dough 1 hour.
Shape dough into a 12-inch log using wax paper. Wrap tightly in plastic wrap, and chill 8 hours.
Preheat oven to 375°. Cut log into 1/4-inch-thick slices. Place 1 inch apart on ungreased baking sheets. Bake 12 minutes or until set. Transfer to wire racks; cool completely (about 15 minutes). Drizzle melted semisweet chocolate morsels over cooled cookies.