Preheat oven to 350˚F. Line a 9”x9” baking pan with foil, making sure that foil comes up over the sides somewhat.
In mixing bowl cream together the sugar and butter for the batter, making sure to stir or blend until the mixture has lightened in both color and texture. Add in eggs and vanilla and stir until fully incorporated.
Slowly add in flour and cocoa powder and mix just until color is uniform. Pour batter into baking dish and bake for 20-25 minutes or until a knife inserted in the center comes out mostly dry with only a few moist crumbs. For the best texture do not overbake.
While brownies are cooling begin to make the frosting. In a medium bowl combine butter, milk, cocoa powder, and powdered sugar until a smooth frosting texture is reached. If mixture is too dry add 1 tablespoon of milk at a time. If too runny, add in one tablespoon of powdered sugar at a time.
Once frosting is the right texture spread over brownies while they are still warm so that some of the icing melts into the brownies. Cut into squares and use the foil to help lift the brownies out of the pan.
