Beat butter at medium speed with an electric mixer until smooth and creamy, about 1 minute.
Scrape down sides of bowl. Add powdered sugar and beat at medium speed until light and fluffy, 2 to 3 minutes.
With mixer running, gradually add cream and vanilla and beat on low speed until smooth, scraping down sides of bowl as needed. Use immediately or cover and store at room temperature for up to 4 days. Buttercream can be refrigerated for up to 2 weeks or frozen for up to 2 months. Bring to room temperature before using.