Whisk <quantity>70<unit>g</unit></quantity> of white sugar with <quantity>5</quantity> egg yolks until fluffy and pale yellow

Mix <quantity>300<unit>g</unit></quantity> of milk and <quantity>300<unit>g</unit></quantity> of heavy cream in a saucepan on medium heat. Bring it to just below the boiling point

Temper the beaten egg yolks with ½ of the hot milk and cream mixture. Whisk until combined

Transfer the tempered egg yolks to the pot with the remaining milk and cream mixture. Whisk constantly and cook over low heat until the custard is thickened. Remove from heat

Let the custard cool down to <temperature>60<unit>°C</unit></temperature>. Add <quantity>4<unit>leaves</unit></quantity> of gelatin. Whisk to dissolve

Add <quantity>250<unit>g</unit></quantity> of 50% cocoa chocolate chunks. Whisk until the chocolate is completely melted

Transfer to a clean bowl and cover it with cling film, pressing lightly against the surface

Place in the refrigerator for 2h until completely chilled

Remove from the refrigerator and beat until the mixture is smooth

Whip <quantity>600<unit>g</unit></quantity> of heavy cream until it becomes firm

Gently fold the whipped cream into the chocolate mixture, little by little, so it stays aerated

Cover the bowl with cling film and refrigerate for 8h until it sets

Add a spoonful to a plate. The chocolate mousse is ready

Enjoy this decadent chocolate dessert!