In large bowl, beat butter with electric mixer until light and fluffy. Gradually add sugar, beating well. Add egg yolk and Toasted Coconut Flavor; mix well. Slowly add flour mixture, beating on low speed until incorporated. Increase speed to medium and beat 2 minutes. Form dough into 2 disks, about 1 in. thick; wrap in plastic wrap. Refrigerate 1 hour or until firm enough to roll.