Coffee German Buttercream
 
Ingredients
  • 1⅓ cups (267 grams) granulated sugar
  • ⅓ cup (40 grams) cornstarch
  • ¾ teaspoon (2.25 grams) kosher salt
  • 2 large eggs (100 grams)
  • 2 large egg yolks (37 grams)
  • 1½ cups (360 grams) whole milk
  • 1½ tablespoons (19.5 grams) vanilla extract
  • 2⅔ cups (604 grams) unsalted butter, softened
  • ¼ cup (12 grams) dark-roast instant coffee granules
  • 1 tablespoon (15 grams) water
Instructions
  1. In a large bowl, whisk together sugar, cornstarch, and salt. Add eggs and egg yolks; whisk until well combined, stopping to scrape sides of bowl.
  2. In a medium saucepan, heat milk over medium heat, stirring frequently, until steaming. (Do not boil.) Gradually whisk warm milk into sugar mixture. Return mixture to saucepan; cook, whisking constantly, until thickened, slightly lumpy, and starting to bubble, about 4 minutes. Cook, whisking constantly, for 2 minutes. Remove from heat. Whisk in vanilla. (Mixture should now be smooth.) Pour into a large baking dish. Cover with a piece of plastic wrap, pressing wrap directly onto surface of custard to prevent a skin from forming. Refrigerate until cool, about 1 hour.
  3. Let custard stand at room temperature for 40 minutes; stir until smooth and softened.
  4. In the bowl of a stand mixer fitted with the paddle attachment, beat butter at medium speed until creamy, smooth, and light, about 4 minutes, stopping to scrape sides of bowl. Add custard, about 1 to 2 tablespoons (16 to 36 grams) at a time, beating until combined after each addition and stopping to scrape sides of bowl.
  5. In a small bowl, stir together coffee granules and 1 tablespoon (15 grams) water until granules are dissolved.
  6. Switch to the whisk attachment. Add coffee mixture to butter mixture, and beat at medium speed until light and fluffy, about 4 minutes. Use immediately.
Recipe by Bake from Scratch at https://www.bakefromscratch.com/coffee-peanut-meringue-cake/