Add softened butter, powdered sugar, vanilla, baking cocoa and 2 Tbsp. milk to the bowl of an electric mixer and turn it on low to begin mixing. Once the ingredients start to come together, stop the mixer, scrape down the sides of the bowl with a spatula, then turn it back on to medium speed until the ingredients start to come together more and don't flip out of the bowl. Stop the mixer, scrape down the sides of the bowl with a spatula, then turn it to high speed for about half a minute. Stop the mixer and scoop some up with a spatula to judge how creamy it is. If the consistency is nice and creamy (it scoops easily and is smooth), scrape down the bowl again, then set a timer for five minutes, and set the mixer to mix on high speed until the timer goes off.

If it needs to be a little more creamy (it probably will), add another Tablespoon of milk and turn on the mixer to see if that does the trick. Mix it on high for another half a minute to see if it's creamy enough. It may need one more Tablespoon, but be careful not to add too much.

After it reaches the desired creaminess, scrape down the sides of the bowl one more time, then set the timer for five minutes and let the mixer mix on high until the timer goes off.