Brown Sugar Caramel Swiss Meringue Buttercream
 
Makes about 3½ cups
Ingredients
  • 3 large egg whites (90 grams), room temperature
  • ½ cup (100 grams) granulated sugar
  • ½ cup (110 grams) firmly packed light brown sugar
  • 1½ cups (340 grams) unsalted butter, softened and cubed
  • Salted Caramel Sauce (recipe follows)
Instructions
  1. In the bowl of a stand mixer fitted with the whisk attachment, whisk together eggs and sugars by hand. Place mixer bowl over a saucepan of simmering water. Cook, whisking occasionally, until mixture registers 155°F (68°C) to 160°F (71°C) on a candy thermometer.
  2. Carefully return bowl to stand mixer, and beat at high speed until medium-stiff peaks form, about 5 minutes. Reduce mixer to low speed. Beat until bowl is cool to the touch, about 8 minutes. Switch to the paddle attachment. With mixer on medium-low speed, add butter, 2 tablespoons (28 grams) at a time, beating until combined. Add Salted Caramel Sauce, and beat until smooth, about 3 minutes. (If buttercream breaks, beat 2 to 3 minutes more, and the emulsion will come back together.) Use immediately, or refrigerate in an airtight container for up to 3 days. If refrigerating, let frosting come to room temperature before using.
Recipe by Bake from Scratch at https://www.bakefromscratch.com/four-buttercream-recipes-every-baker-should-know/