Pour the cream, the milk and sugar into a saucepan. Stir to combine.
Then add the agar agar and mix well.
Lastly, add the black sesame paste and whisk so that the paste dissolves well into the mixture.
Put the pan on medium heat and heat the mixture until it boils.
Once boiling, allow to heat for a further 4 minutes, whisking regularly. The mixture should be a little thicker, but still be liquid.
Pour into 6 ramekins. Leave to cool for about 20 minutes before placing in the fridge for at least 90 minutes (or more if you make them in advance).
When ready to serve, you can unmould the panna cotta by running the blade of a thin knife along the side of the ramekin or serve it directly in the ramekin. Then add the coulis of your choice. You can sprinkle with a few black sesame seeds on top.