Preheat your oven to 390°F (200°C). Melt the butter with the chocolate. Mix the almond flour and the icing sugar together.
Beat the eggs with the sugar faster and faster during about 5 minutes. Incorporate slowly the almond + icing sugar mix and then the melted chocolate + butter mix.
Pour the batter in a buttered mold and bake 5 minutes at 390°F (200°C). Then, bake it during 25 minutes at 320°F (160°C).
Let it cool down, unmold and that's it ! You can now sprinkle some icing sugar and flaked almonds on top of it!