In a medium saucepan, over medium heat, melt 1 3/4 sticks of butter. Once the butter is melted add 4 TBSP unsweetend cocoa. Stir until well combined. Turn the heat to low and add the whole milk, vanilla and powdered sugar. Stir together until well combined. Continue to stir after it is well combined for several minutes over low heat. The mixture should be smooth.