Heat oven to 350°F (180°C). Grease and flour or spray with non-stick cooking spray a 12-cup (3 L) fluted tube cake pan. Make cake batter as directed on box. Pour about 2 cups (500 mL) batter into pan.
Into small bowl, pour about 3/4 cup (175 mL) batter; stir in food colour and peppermint extract. Carefully pour pink batter over white batter in pan. Carefully pour remaining white batter over pink batter.
Bake 33 to 38 minutes or until toothpick inserted in centre comes out clean. Cool in pan 15 minutes; turn upside down onto cooling rack; cool completely, about 1 hour.
Remove foil from tub of frosting. Stir. Microwave on medium power for 30 to 45 seconds or until it is a good consistency for pouring. Pour over cake. Sprinkle with crushed candies if desired. Store loosely covered.