Chocolate Mousse Frosting

Let's Cook

1. Step 1.

   Whisk together in a medium heatproof bowl, preferably stainless steel: 2 large eggs; 2 cups powdered sugar, sifted; ½ cup milk, coffee, or water; ⅛ teaspoon salt

2. Step 2.

   Set the bowl in a large skillet of barely simmering water and heat, stirring constantly, until the mixture registers 160°F on an instant-read thermometer. Remove from the heat and stir in: 4 ounces unsweetened chocolate, finely chopped; 6 tablespoons (¾ stick) unsalted butter, cut into small pieces; 1 teaspoon vanilla

3. Step 3.

   Stir until the chocolate and butter are melted and the mixture is smooth. Set the bowl in a larger bowl of ice water and beat on high speed until the frosting holds a shape, 7 to 10 minutes. This keeps, refrigerated, for up to 4 days.