Mix agar-agar with a small portion of the orange juice. Bring the remaining orange juice with sugar in a saucepan to a boil. Stir in agar-agar and cook for about 2 minutes. Let it cool down a little, fill into glasses and let it set in the refrigerator for 30 minutes.

Whip the chickpea water with cream of tartar and lemon juice and, if necessary, a pinch of salt (only if the chickpea water does not contain salt) with an electric whisk on full power until the mixture has the desired consistency. This usually takes a couple of minutes. Add the sugar after 2/3 of the time.

Break the chocolate into pieces and melt over simmering water. Let it cool down slightly. Carefully fold the aquafaba (= whipped chickpea egg white) carefully into the chocolate in portions. Now also pour the mousse into the glasses and, depending on the size of the glasses, put them in the refrigerator for at least 1-2 hours.

Serve sprinkled with grated chocolate. If you used fresh oranges for the orange juice, you can also add some orange zest to the chocolate mousse.