Dark Chocolate Mousse Recipe

Melt chocolate and butter

Place the chopped dark chocolate and butter in a heatproof bowl. Set the bowl over a saucepan of barely simmering water (double boiler) without the bowl touching the water. Stir occasionally until fully melted and smooth, about 3–5 minutes. Remove from heat and let cool slightly (about 5 minutes).

Whisk egg yolks and sugar

In a medium bowl, whisk the egg yolks with 2 tablespoons granulated sugar until the mixture is pale and slightly thickened, about 1–2 minutes. Whisk in the vanilla extract and a pinch of salt. Slowly whisk about 2 tablespoons of the warm melted chocolate into the yolk mixture to temper it, then whisk the yolk mixture back into the remaining melted chocolate until fully combined. Set aside to cool slightly.

Beat egg whites

In a clean, dry bowl, use an electric mixer to beat the egg whites to soft peaks. Gradually add the remaining 1 tablespoon granulated sugar and continue beating until glossy, stiff-ish peaks form but not dry.

Whip cream for folding

In a separate chilled bowl, whip 1 cup heavy cream until it holds soft peaks. It should be light and billowy but still foldable.

Fold components together

First fold one-quarter of the whipped cream into the chocolate-yolk mixture to lighten it, using a large spatula. Then fold in the remaining cream gently until streaks disappear. Next, fold in one-third of the beaten egg whites to loosen the mixture, then gently fold in the remaining egg whites until no white streaks remain. Work gently to preserve air for a light mousse.

Portion and chill

Divide the mousse among 4–6 serving glasses or ramekins. Smooth the tops, cover with plastic wrap (directly on the surface to prevent a skin) and refrigerate at least 2 hours, preferably 3–4 hours, until set and chilled.

Line a small baking sheet with parchment paper. In a small nonstick skillet over medium heat, combine the sugar and water. Stir until the sugar dissolves and begins to simmer, about 1–2 minutes. Add the pistachios and toss to coat in the syrup. Continue cooking, stirring frequently, until the sugar crystallizes and then melts to form a glossy coating on the nuts, about 3–5 minutes. Immediately spread the pistachios onto the prepared parchment and separate them with a fork if they clump. Sprinkle a pinch of fine sea salt over them while still warm. Let cool completely, then roughly chop or leave whole for garnish.

About 10 minutes before serving, whip 3 tablespoons heavy cream with 1 teaspoon powdered sugar and 1 teaspoon vanilla extract until soft peaks form. Spoon or pipe a dollop of whipped cream onto each chilled mousse.

Top each mousse with a sprinkle of candied pistachios and, if desired, a pinch of chocolate shavings. Serve immediately.