Beat butter on medium-high speed until pale and creamy, about 2 minutes. Reduce speed to medium and add sugar, 1/2 cup at a time, beating after each addition, until combined, 1 to 2 minutes total. (After every 2 additions, increase speed to high and beat for 10 seconds, then reduce speed to medium.) Beat in vanilla until smooth.
Add food coloring, a little at a time, to achieve desired color. Use immediately, or store in an airtight container in refrigerator up to 3 days. To use, bring to room temperature and beat on low speed until smooth.