Preheat the oven to 170°C (340°F). Grease a springform pan (about 22–24 cm / 9–10 inches) and line the bottom with parchment paper.

Melt the dark chocolate in a bain-marie or gently in the microwave (30-second intervals). Stir in the butter and mix until smooth. Let cool slightly

Beat the egg yolks with the Tagatesse and vanilla extract until pale and creamy.

Fold the chocolate-butter mixture and the almond flour into the egg yolks.

In a clean, grease-free bowl, beat the egg whites with a pinch of salt until stiff peaks form.

Gently fold the beaten egg whites into the chocolate mixture. Do not overmix to keep the batter light and airy.

Pour the batter into the pan and bake for 35–40 minutes. The center may remain slightly moist (moelleux).

Let the cake cool in the pan for 15 minutes, then remove the ring and allow to cool completely on a wire rack.

Festive touch: Drizzle melted dark chocolate over the cake and sprinkle with toasted sliced almonds.