For her Bûche de Noël (Yule Log) cake that we featured in the Nov/Dec 2015 issue, Joëlle Mahoney used a mocha buttercream to fill her rolled sponge cake.We didn’t have room for it in the issue, but here it is. Thanks Joëlle!
2 tbsp instant espresso powder
2 tablespoons boiling hot water
4 large egg whites, room temperature
1 1/4 c sugar
3 sticks unsalted, high quality butter, cut into small pieces, at room temperature.
4-6 ounces good quality, semisweet chocolate, coarsely chopped, melted to a maximum of 89ºF.
- Dissolve the espresso powder into the boiling water in a small bowl. Allow to cool completely.
- Place egg whites and sugar in a heat proof bowl of an electric mixer set atop a pan of simmering water. Immediately begin hand whisking until whites are warm to the touch and the sugar is completely dissolved. This will take at least 3 minutes.
- With an electric mixer, whisk egg white mixture on medium-high until stiff, shiny peaks form. Approximately 10 minutes.
- Reduce speed of mixer to medium-low. Add the butter, a few pieces at a time, making sure they are well incorporated into the mixture. At this point, you must switch from the whisking attachment to the paddle attachment of your mixer, and reduce speed to low.
- Add espresso mixture and melted chocolate, mix until smooth, approximately 5 minutes.
- Allow to chill in the refrigerator for 15-20 minutes covered with a plastic wrap. Then, remove from the refrigerator and set aside on counter until ready to use.
Makes approximately 3 cups.