• Preheat oven to 350°F. Line a 9x9 (or 8x8) pan with parchment paper or grease the pan very well with non-stick cooking spray.

For the brownies

• In a large microwave-safe bowl, add butter, both sugars and cocoa powder. Microwave for 1 minute and 30 seconds. Stir very well until combined. Add the eggs and vanilla and stir until incorporated. Add the flour and baking powder and mix until combined. The batter will be very thick.
• Pour mixture into prepared pan and bake for 25-27 minutes or until a toothpick inserted in the center comes out with a few moist crumbs. Allow brownies to cool completely.

For the frosting

• In a large bowl, cream the butter and corn syrup until completely smooth. Add the cocoa powder and vanilla and beat until smooth. Add the powdered sugar and mix on low until completely incorporated. The frosting will be extremely thick at this point. Add the milk 1 tablespoon at a time and beat for about one minute until smooth and creamy.
• Spread a thick layer of frosting on top of the cooled brownies. Slice into bars and serve.