Add two cups of coke to a large pot and boil it down for 20-30 minutes stirring infrequently.
After 20-30 minutes the coke should be reduced to a runny syrup consistency, chill in the refrigerator for about 15-30 minutes until cool to the touch.
With an electric mixer, beat butter on medium for 1 minute.
Add the coke and mix thoroughly.
Add the powdered sugar and milk.
Recipe by Wanna Bite at https://wannabite.com/coke-buttercream-frosting/