Heat oven to 350°F. Grease bottom only of 13x9-inch baking pan. Set aside.
Melt 1 1/4 cups butter and chocolate in 3-quart saucepan over low heat, stirring occasionally, 6-10 minutes or until smooth. Remove from heat; stir in sugar. Add eggs and 1/2 teaspoon peppermint extract; beat just until mixed. Stir in flour and salt; mix just until all ingredients are moistened and brownie mixture is smooth.
Spread batter into prepared pan. Bake 30-35 minutes or until brownie just begins to pull away from sides of pan. (Do not overbake.) Cool completely.
Combine all frosting ingredients except milk and food color in bowl. Beat at low speed, gradually adding enough milk and scraping bowl often, for desired spreading consistency. Stir in food color, if desired, until well mixed.
Drizzle frosting over brownies. Sprinkle with candy; gently press into frosting. Cover; refrigerate until frosting is set. Cut into bars.