Ingredients

  • For the pastry cream:
  • 9 1/2 ounces (1 cup plus 3 tablespoons) whole milk
  • 3 1/2 ounces (1/2 cup) granulated sugar, divided
  • 1 ounce (1/4 cup) cornstarch
  • 4 ounces (about 2 large) eggs
  • 1 ounce (2 tablespoons) unsalted butter, at room temperature
  • For the final buttercream:
  • 1 pound (2 cups) unsalted butter, at room temperature
  • 4 ounces (1 cup) confectioners' sugar, sifted
  • 1 1/2 teaspoons vanilla extract

Method

  • In a small pot, bring the milk and half of the sugar to a simmer over medium heat. While the milk heats, whisk the remaining sugar with the cornstarch. Place the eggs in a medium, heat-safe bowl.
  • When the milk is hot, whisk the sugar/cornstarch mixture into the eggs to fully combine. Gradually add the milk to the egg mixture in a slow, steady stream, whisking constantly. Don't dump the milk in too fast, or you risk scrambling the eggs!
  • Return the mixture to the pot and cook until the mixture comes to a boil-large bubbles should emerge from the center of the pot. Remove the pot from the heat and mix in the 2 tablespoons of butter.
  • Transfer the pastry cream to a shallow bowl and cover directly with plastic wrap. Chill the pastry cream in the refrigerator for at least 1 hour.
  • Transfer the cooled pastry cream to the bowl of an electric mixer fitted with the whisk attachment, and whip for 1 to 2 minutes, to aerate. While the mixer is running, gradually add room temperature butter in 1/2-tablespoon chunks. Continue adding and mixing until all of the butter is added and the buttercream is light and smooth.
  • Beat in the powdered sugar and vanilla, mix to combine. The buttercream can be used immediately or refrigerated in an airtight container.