Chocolate Mousse Buttercream Frosting {3 ways}


  • PREP TIME:25 minutes
  • COOK TIME:5 minutes
  • TOTAL TIME:30 minutes
  • YIELD:Makes enough to frost and fill a 3-layer 8-inch cake.

Rich Milk Chocolate Mousse Buttercream made from a chocolate ganache base with no added powdered sugar that is creamy, light and fluffy, silky smooth, and reminiscent of the dessert by the same name. This dreamy chocolate buttercream frosting is sweetened just right and pipes beautifully. Variations include Dark Chocolate Mousse Buttercream and Mocha Mousse Buttercream. Ideal for frosting Chocolate Mousse Cake—a baker and chocolate dessert lover’s dream come true!


  • For Milk Chocolate Mousse Buttercream
  • 10 ounces (284 grams) fine-quality milk chocolate, chopped
  • 6 ounces (170 grams) fine-quality dark chocolate, chopped
  • 1½ cups (360 ml) heavy cream
  • 2 tablespoons (30 ml) golden syrup, such as Lyle’s (or corn syrup)
  • 1 cup (2 sticks/226 grams) salted butter, slightly softened
  • ¾ cup (1½ sticks/170 grams) unsalted butter, slightly softened


  1. Place both chocolates in the bowl of a stand mixer. In a small saucepan, bring the cream and syrup to a boil. Remove from the heat and immediately pour the hot cream mixture over the chocolate. Let stand until chocolate is melted, about 2 to 3 minutes. Starting in the center of the bowl, whisk the chocolate and cream mixture by hand until completely smooth. Set aside to cool to room temperature.
  2. Once the chocolate mixture has cooled, add the softened but still cool butter. Return the bowl to stand mixer fitted with whisk attachment. Beat on medium speed until mixture is well blended and thoroughly combined. At this point, the frosting should be completely smooth with a silky appearance.
  3. Chill frosting in bowl in the freezer for 5 minutes. Stir with rubber spatula. Repeat 3 to 4 more times to reach desired mousse consistency. Return bowl to stand mixer fitted with whisk attachment and whip until mixture is light and fluffy like mousse. Buttercream is now ready to use.

Recipe Notes


For Dark Chocolate Mousse Buttercream:

  • Omit milk chocolate and use 16 ounces (454 grams) dark chocolate.

For Mocha Mousse Buttercream:

  • Add 2 to 3 teaspoons espresso powder (granules) into boiling cream mixture and stir until dissolved before pouring over chocolate.


  • If not using immediately, the buttercream can be refrigerated for up to 1 week in an airtight container. Storing longer than this is not recommended due to the dairy content. Slowly bring closer to room temperature, but not quite, before beating and frosting cakes or cupcakes.
  • If using the buttercream to pipe details, be sure to use chilled hands when handling pastry bag as warm hands can easily melt the buttercream.This buttercream will last for up to 3 days at room temperature when on a frosted cake, covered.

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