1Heat oven to 350°F. In large bowl, beat brown sugar, granulated sugar, butter, shortening, vanilla and eggs with electric mixer on medium speed until smooth. Beat in melted baking chocolate. On low speed, beat in flour and baking soda until well blended. Reserve 1 cup of the chopped mints. Stir remaining mints and the chocolate chunks into dough.
2On ungreased cookie sheets, drop dough by 1/4 cupfuls 2 inches apart.
3Bake 11 to 15 minutes or until centers of cookies no longer look moist (do not overbake). Immediately sprinkle with reserved mints. Cool 1 minute; remove from cookie sheets to cooling racks.