Prepare a bain marie on a stove (a pot with hot water and another pot on top of it)
In another stove, place a pot and fill in with milk, cream, sugar. Bring it to boil.
Take two ladle of lukewarm milk mixture into a bain marie top bowl, pour in the egg yolks in order to temper the egg (to prevent the egg overcook and become scrambled)
Place the pot on bain marie while whisking it.
When the milk is boiled, switch off the heat. Slowly pour the milk into the egg mixture. Whisking it until it is smooth and little thicker for 4-6 mins.
Remove the pot from bain marie, add the chopped chocolate. Whisk it well until chocolate melted. Set aside while cooling it down.
In a mixer pot, pour the cream and mix it well until stiff.
If the chocolate is still very warm, you may put a minute in ice bath. (Optional)
Slowly whisk in the whipped cream into chocolate mixture until good incorporated and shiny.
Pour the chocolate mousse into individual serving glasses or any containers. Cool it down.
Tips. You may use gelatine, if you use the chocolate mousse for the cake.
