Preheat the oven to 180°C (356°F).
Melt the dark chocolate and butter together using a double boiler.
Whip the eggs and sugar until foamy.
Add the melted chocolate and butter mixture to the egg mixture and mix well.
Sift in cake flour, almond flour, baking powder, and cocoa powder, and gently combine.
Pour the batter into a madeleine mold.
Bake in the preheated oven for 10–12 minutes.