Next, we’ll whip the egg whites! In a clean mixing bowl, I add the egg whites and a pinch of salt. Using my electric mixer, I whip them until soft peaks form, then gradually add half of the granulated sugar. Keep mixing until stiff peaks form. In another bowl, I whisk the egg yolks with the remaining sugar, vanilla extract, orange zest, and juice until it’s pale and creamy. The combination of flavors has my kitchen smelling divine!
Now, it’s time to fold! Carefully combine the melted chocolate with the egg yolk mixture. Then, gently fold in the whipped egg whites using a rubber spatula. Be patient and avoid deflating the mixture, as this will help keep the mousse light and airy. Once that’s well combined, I whip the heavy cream until soft peaks form and fold that in as well—it’s this step that gives the cake its divine creaminess.
Pour the mousse mixture into a 9-inch springform pan, smoothing the top with an offset spatula if you have one. Cover it with plastic wrap and place it in the refrigerator to set for at least 4 hours, preferably overnight. Trust me, the waiting will be worth it! (See the next page below to continue steps…)