Heat oven to 350F. Spray 15 regular-size muffin cups with cooking spray.
In a large bowl, combine brownie mix, water, oil and eggs. Fold in chopped Zing Dark Chocolate Mint Bar. Fill muffin cups two-thirds full of batter and bake for 15 to 18 minutes or until edges are dry but centers are still slightly soft. Cool 5 minutes in cups, then remove to a cooling rack to cool completely while you make frosting.
In a medium bowl, beat frosting ingredients with an electric mixer on medium-high speed until smooth and creamy. Pipe frosting on tops of cooled brownie cups.
Place chocolate glaze ingredients in a heatproof bowl set over a saucepan of simmering water. Stir frequently as mixture melts; remove from heat just when no lumps remain. Pour a spoonful over frosting on each cup. Let stand 15 minutes before serving.