1. Heat oven to 350°F. Grease 13x9x2-inch baking pan.
2. Stir together cocoa and baking soda in large bowl; stir in 1/3 cup butter. Add water; stir until mixture thickens. Stir in sugar, eggs and remaining 1/3 cup butter; stir until smooth. Add flour, vanilla and salt; stir until well blended. Stir in mint chocolate chips. Spread batter in prepared pan.
3. Bake 35 to 40 minutes or until brownies begin to pull away from sides of pan. Cool completely in pan on wire rack. Drizzle GLAZE over top, if desired. Cut into bars. Makes about 24 brownies.
GLAZE: Stir 2/3 cup powdered sugar and 2 to 3 teaspoons milk in small bowl; stir in few drops green food color, if desired.