In a stand mixer fitted with a paddle attachment, beat the butter on medium speed for about 1 minute.
Add the powdered sugar one cup at a time. Stop the bowl to scrape down the bottom and sides of the bowl.
Add the black cocoa powder and mix until smooth.
Add the melted chocolate, vanilla, anise oil and mix until combined.
Slowly add in the whipping cream. Turn off the mixer to scrape the sides and bottom of the bowl.
If you want your buttercream pitch black add the black food gel at this time.
Mix on medium high speed for 3-5 minutes.
Taste the buttercream and if you want a stronger licorice flavor add a little more oil/flavoring until you get to your desired taste.