In a stand mixer with the whisk attachment, beat butter at medium-high speed until smooth, about 20 seconds.
Add icing sugar in thirds; beat at medium-low speed until mixed. Scraping down as required.
Add extract and heavy cream, and beat at medium speed until incorporated, about 10 seconds.
Then increase the speed to medium-high and beat until light and fluffy, about 4 minutes, scraping down bowl once or twice.