In a stand mixer fitted with a paddle attachment, cream the butter.
With the mixer on low speed, add the powdered sugar one cup at a time. Occasionally stop the mixer to scrape down the sides and bottom of the bowl with a rubber spatula.
Once the powdered sugar is mixed in, add the apple butter and mix until incorporated.
Increase speed to high and whip for 5 minutes stopping once to scrape down the sides and bottom of the bowl.
Stir slowly for about a minute to remove air bubbles.