1 cup unsalted butter
4 1/2 cups powdered sugar
1 Tbsp. vanilla
4-5 Tbsp. cream or milk

  • beat butter in stand mixer until creamy, about 2 minutes
  • mix in powdered sugar in small batches
  • mix in vanilla
  • mix in cream/milk one Tbsp. at a time until desired thickness is reached

source: https://belleofthekitchen.com/the-best-vanilla-buttercream-frosting/