Bittersweet Chocolate Swiss Meringue Buttercream


When whipping the butter into the cooled meringue, youâll usually find the mixture separating and starting to look curdled. Donât worry! Keep whipping at high speed and adding the butter and it will soon come together.

Always add the softened butter AFTER the meringue has cooled. If the meringue is still warm, the butter will only melt and you’ll end up with a liquidy mess.

This type of buttercream should be refrigerated if it is not being used or eaten within a couple of hours.

Bittersweet Chocolate Swiss Meringue Buttercream


  • 1 pound bittersweet chocolate
  • 12 ounces semisweet chocolate

  • 3/4 cup egg whites (4 to 5 extra-large eggs), at room temperature
  • 1 1/2 cups granulated sugar
  • 1/4 teaspoon cream of tartar
  • 3/4 teaspoon kosher salt
  • 1 1/2 pounds unsalted butter, at room temperature
  • 3 teaspoons pure vanilla extract
  • 3 teaspoons instant espresso powder, dissolved in 1 1/2 teaspoons water
  • 3 tablespoons dark rum, optional


  1. Chop the chocolates and place them in a heat-proof bowl set over a pan of simmering water. Stir until melted and set aside until cooled to room temperature.
  2. Mix the egg whites, sugar, cream of tartar, and salt in the bowl of an electric mixer fitted with a whisk attachment.
  3. Place the bowl of egg whites over a pan of simmering water* and heat the egg whites until warm to the touch (should be 160 degrees F), about 5 minutes.
  4. Return the bowl to the electric mixer and whisk on high speed for 5 minutes, or until the meringue is cool and holds a stiff peak.
  5. Add the butter, 1 tablespoon at a time, while beating on medium speed.
  6. Scrape down the bowl, add the melted chocolate, vanilla, espresso, and rum, if using, and mix for 1 minute or until the chocolate is completely blended in.
  7. If the buttercream seems very soft, allow it to cool, and beat it again.
  8. *Don’t let bowl touch the simmering water (or the the egg white mixture will heat too quickly and could coagulate).

Comments (1)


Hi, I just made something like this just recently (without the espresso powder and rum) and I was if this will make it darker? Mine came out VERY VERY light. I just want it darker, like the regular chocolate fudge. Do you have any tips? or should I just color it brown?