Add the softened butter to a large mixing bowl and beat with an electric mixer for 1 to 2 minutes, or until smooth and creamy.
Add the powdered sugar, 3 tablespoons of heavy cream, and the vanilla and peppermint extracts.
Beat on low speed until the ingredients are combined, then increase to medium-high speed and beat for 2 to 3 minutes, or until the frosting is light and fluffy.
Add the remaining heavy cream, if needed, until the frosting reaches your desired consistency.
Spread the frosting over completely cooled brownies, cupcakes, or cake. Garnish with crushed candy canes and enjoy.