Preheat oven to 350°. In a large bowl, cream butter and sugar until light and fluffy, 5-7 minutes. Beat in egg, orange zest, lemon zest and extracts. In another bowl, mix flour, cornstarch, baking soda and salt; gradually beat into creamed mixture.
Drop by rounded teaspoonfuls 2 in. apart onto parchment-lined baking sheets. If desired, top with orange peel strips.
Bake 6-8 minutes or until edges are golden brown. Remove from pans to wire racks to cool.