Heat oven to 200°F. Line 2 large cookie sheets with cooking parchment paper.
In medium bowl, beat egg whites and cream of tartar with electric mixer on low speed until foamy. Gradually add sugar, beating on high speed just until stiff peaks form. Beat in spearmint extract and food color. Fold in 1/2 cup of the chocolate chips. Onto cookie sheets, drop meringue by tablespoonfuls about 1 inch apart. Bake 2 hours. Turn oven off; let meringues stay in oven with door closed overnight.
In small microwavable bowl, microwave shortening and remaining 1 cup chocolate chips uncovered on High 1 to 2 minutes, stirring every 30 seconds, until melted and chips can be stirred smooth. Dip bottom of each cookie into melted chocolate. Return to cookie sheets; let stand 2 hours until chocolate is set. Store loosely covered at room temperature.