Preheat oven to 350°F (175°C) and grease an 8×8-inch pan
Melt the butter, then let it cool slightly, then mix in sugar, eggs, and vanilla until smooth
Add cocoa powder, flour, salt, and baking powder. Mix just until combined and spread evenly into the pan
Bake for 25 minutes. Do not over bake. Slightly soft is the goal
Whisk all frosting ingredients until smooth
Spread frosting over brownies while still warm so it melts right in
