Mousse Au Chocolat Recipe

Melt chocolate

Place the chopped chocolate and butter in a heatproof bowl set over a barely simmering saucepan of water (double boiler). Stir occasionally until smooth and fully melted, about 3–5 minutes. Remove from heat and let cool slightly while you prepare the other components (target temperature about 35–40°C / warm to the touch).

Whisk yolks with sugar

In a medium heatproof bowl, whisk the 4 egg yolks with 40 g granulated sugar until well combined. Set the bowl over a saucepan of simmering water (bain-marie), making sure the bowl bottom doesn't touch the water. Whisk constantly until the mixture becomes warm, slightly thickened and paler, and the sugar is dissolved (about 3–4 minutes). Remove from heat.

Temper and combine with chocolate: Immediately whisk about one-third of the warm melted chocolate into the yolk mixture to temper it, then pour the yolk-chocolate mixture back into the bowl with the remaining melted chocolate and stir until smooth. Add vanilla extract and mix to combine. Allow to cool to lukewarm while proceeding with whipped cream and egg whites.

Whip cream

Chill a mixing bowl and whisk (or use the bowl of a stand mixer). Pour the cold heavy cream and powdered sugar (if using) into the bowl. Whip on medium-high speed until soft peaks form — the cream should hold a gentle peak but still be pliable. Do not overbeat into grainy butter. Reserve about one-quarter of the whipped cream for folding and to lighten the chocolate first.

Beat egg whites

In a very clean, dry bowl, whisk the room-temperature egg whites with a pinch of salt until frothy. Gradually add 20 g granulated sugar and continue whisking to stiff glossy peaks. The whites should stand up firmly but not look dry.

Lighten the chocolate: Fold the reserved quarter of whipped cream gently into the cooled chocolate-yolk mixture to loosen it, using a silicone spatula and folding motion (cut through center, lift and turn).

Fold in egg whites: Add about one-third of the beaten egg whites to the chocolate-cream mixture and fold gently to further lighten. Then fold in the remaining egg whites in two additions, folding just until no white streaks remain. Work gently to keep as much air as possible.

Finish with remaining whipped cream: Fold the remaining whipped cream into the chocolate mixture until homogeneous and light. Taste and adjust by adding a tiny pinch of salt or a few drops of vanilla if needed.

Portion and chill: Spoon or pipe the mousse into serving dishes or a large bowl. Smooth tops and cover with plastic wrap (touching the surface to prevent skin). Chill in the refrigerator at least 2 hours, preferably 4 hours, until set and airy.

Serve chilled: Just before serving, garnish with a light dusting of cocoa powder, a few flakes of sea salt, grated chocolate, or fresh berries if desired. Mousse will keep refrigerated for up to 3 days; for best texture eat within 48 hours.