Preheat oven to 350 degrees.
Add 3 sticks of softened butter and 2 cups of sugar to a mixing bowl.
Mix with a mixer until blended and smooth.
Add vanilla and eggs and start the mixer again until well combined.
In a separate bowl, whisk together cocoa powder, 1/2 tsp salt, and flour until well combined.
Add the whisked dry ingredients and 1 cup of milk to the mixing bowl (that has the butter mixture still in it) and mix with mixer until well combined.
Pour the batter into a greased 9x13 baking dish and spread it out evenly.
Bake in the oven 35-45 minutes, until you can insert a toothpick in the middle and remove without any brownie batter sticking to the toothpick.
Let the brownies cool completely and then work on making the frosting.
In a saucepan on the stovetop, add 6 TBSP of milk and 6 TBSP of butter. Heat on low until butter is melted. Add 1 1/2 cups of sugar and whisk until well combined. Bring the mixture to a boil, stirring occasionally, and then turn off the heat and add chocolate melting wafers and 1/2 tsp salt. Whisk until well combined and smooth.
Pour the chocolate frosting over the brownies.
Spread the frosting evenly over the brownies. Allow to cool completely (frosting will harden as it cools).
Serve and enjoy!