Instructions

  1. In 2-quart saucepan, thoroughly combine sugar and flour.
  2. With wire whisk, gradually stir in milk until smooth.
  3. Cook over medium-high heat, stirring frequently, until mixture has thickened and boils.
  4. Reduce heat to low; cook 2 minutes, stirring constantly.
  5. Remove from heat and cool completely.
  6. In medium bowl, with mixer at medium speed, beat butter until light and fluffy.
  7. Gradually beat in milk mixture; beat in vanilla.