Room temp butter is perfect for this! Yes... Yes that's 16 oz of butter... Use all of it! :)
Now I have a love hate relationship with this step... Add sugar to taste my monsters love that sweet stuff so I use about 4 cups. Eeeeek!!
Vanilla if you like 1 table spoon or you can add cocoa at this point till it's as chocolate tasting as you like keep in mind more cocoa means more powdered sugar
Throw it all in this baby here!!!
Mix till smooth and creamy ( yes it's a smaller amount than what you will end up with I had previously made some and then saw the guide request!! )
Taste test!! Oops. ... You caught me!!!!!