Preheat the oven at 230°C.
Melt the chocolate and butter by placing a bowl on top of boiling water. Keep on steering to make sure the butter and chocolate mix properly.
In a small bowl, mix the cacao powder and milk. Mix till smooth, it should be as thick as the melted chocolate.
In a different bowl, whisk the eggs, egg yolks, agave syrup and vanilla extract with a handmixer.
Carefully stir in the melted chocolate and cacao powder mixture in the egg mix.
Add the salt and flour. Stir again till smooth.
Butter 6 ramekins, add a table spoon flour to each ramekin and make sure it fully covered with flour. Throw away the leftover flour.
Add the batter into the ramekins and bake for 7-8 minutes.
Let it rest for a few minutes. Top with powdered sugar.