Combine 1 cup butter, 1/2 cup powdered sugar and 1/2 teaspoon peppermint extract in large bowl. Beat at medium speed, scraping bowl often, until creamy. Reduce speed to low; add flour and cornstarch. Beat until well mixed. Cover; refrigerate until firm (30 to 60 minutes).

Shape rounded teaspoonfuls of dough into 1-inch balls. Place 2 inches apart onto ungreased cookie sheets.

Bake in at 350F for 12 to 15 minutes or until edges are lightly browned. Let stand 1 minute; remove from cookie sheets. Cool completely.

Drizzle glaze over cooled cookies. To make glaze, combine powdered sugar, butter, peppermint extract and enough milk for desired consistency in small bowl. Stir in food color, if desired. Immediately sprinkle with crushed candy.