Soak chopped agar agar in 1 1/2 cup milk for 10 minutes. Simmer for 15 minutes whisking well to dissolve the agar agar flakes thoroughly.
In the mean time mix powdered sugar, cream and vanilla. Mix thoroughly and set aside.
Once the agar agar flakes have dissolved well in the simmering milk, add cocoa powder and mix well. Mix and whisk well to make a smooth mixture.
Filter this to remove remaining agar agar flakes if any.
Add this cocoa milk mixture to the sweetened cream and mix well.
Pour in molds and set aside for 3-4 hours. Actually it well set within 30 minutes. Sitting time is for the dessert to chill. unmold and serve chocolate panna cotta chilled
Notes
1. I made in a regular 6 cavity muffin tin and got 6 small servings perfect as dessert . 2. You can add chopped dark chocolate instead of cocoa powder.