Heat oven to 350°F. Spray 9 or 8-inch square pan with nonstick cooking spray. In large bowl, combine brownie mix and baking powder; mix well. Add milk, butter, vanilla and chocolate syrup from packet in brownie mix; mix well. Spread in greased pan.
Bring water to a boil in medium saucepan. Add espresso granules; stir to dissolve. Add frosting; cook and stir over low heat until melted and smooth. Slowly pour over batter in pan. DO NOT STIR.
Bake at 350°F. for 40 to 45 minutes or until edges are bubbly and cake begins to pull away from sides of pan. (Top may appear shiny in spots.) Cool 30 minutes. Serve warm or chilled with whipped cream. Store in refrigerator.