Whip the cream until soft. Don't over whip it or it starts to go tough and it can split. Reserve in the fridge.
Melt the chocolate in the microwave in 30 second intervals, stirring in between.
Whip the egg yolks in a clean bowl while you put the water and sugar to boil on high heat. As soon as it breaks into a rolling boil add to the yolks slowly as they're whipping up. Let them become thick and cool to room temperature while whipping on high speed.
Mix the chocolate with the egg yolks using a spatula and folding motions.
Whip the egg whites in a clean bowl until foamy. Mix half of it into the yolks and chocolate quickly and then add the rest in using folding motions.
Mix the whipped cream using folding motions.
Spread evenly onto the brownie and take to the fridge for at least 4 hours, ideally overnight.
Umould the cake and carefully remove the paper from around the cake and also from the bottom.