In a mixing bowl, beat the egg yolks and sugar until the sugar is melted.
Heat the heavy cream in a saucepan. Remove from stove and add a 3-4 tablespoons of hot heavy cream to the yolk mixture. Mix well then add a few more tablespoons, then add about 1/2 cup of the hot cream. Mix well.
Transfer the tempered egg mixture to the saucepan and keep cooking until bubbly.
Add the chocolate and mix until the chocolate is melted, stirring continuously.
Remove from heat and cool the pudding completely. Chill in the fridge for an additional hour. Keep the beaters in the fridge too.
Beat the pudding for a couple of minutes, with the mixer on high.
To make the whipped cream
Using chilled beaters, bowl and heavy cream, mix the sugar and heavy cream until you get stiff peaks and the sugar is completely incorporated into the heavy cream.
To make the mousse
Transfer the chocolate pudding to the whipped cream and mix with a hand mixer on medium. Add to individual cups with a spoon or by pipping the mousse. Chill in the fridge for a couple of hours before serving.