Preheat oven to 350 degrees, grease a 9x13 pan and set aside.
To make the frosting: sift together sugar, cocoa and salt. Cream butter in mixing bowl. Gradually add in sugar to butter, alternating with milk. Mix until creamy. Set aside.
In a large mixing bowl, whisk together melted butter, cocoa and sugar. Stir in flour and beat well. Add vanilla and eggs, one by one, and mix just to combine.
Spread batter evenly and into corners with an offset spatula in prepared pan. (Batter will be thick)
Bake for 22-25 minutes or until toothpick inserted in center comes out clean. Spread frosting over warm brownies.