Keep 6-cup molds/ ramekins/ bowls ready.
Combine heavy cream, milk and sugar in a heavy bottomed pan; bring the mixture to a boil.
Low the heat and add the agar powder. Whisk continuesly until it completely dissolves; simmer for 2-3 minutes.
Remove from heat and then stir in chopped chocolate. Whisk well to melt the chocolate.
Next add the vanilla and mix again.
Pour the mixture into the selected molds/ bowls. Cool a little bit, then refrigerate for at least 3-4 hours.
When ready to serve, dip the mold in hot water and run a sharp paring knife around the edges and then invert onto the serving plate.