Preheat oven at 170 degrees.
Take 200 grams of semi-sweet dark chocolate and cut it into small pieces.
In a pan boil the water into simmering, place a large crystal bowl with the chocolate in it. Melt the chocolate into a double boiler into a silky consistency.
Place it aside to let the melted chocolate cool.
Take four eggs, separate whites, and yolks in a bowl.
Beat the whites until a firm peak.
Mix the egg yolks in a melted chocolate one by one and gently mix it.
Portion the eggs white and mix the first portion thoroughly into a chocolate batter, fold the rest of the egg whites gently.
Take a 6 inches pan and lined with parchment paper.
Pour the batter in it. Tap the pan for 2-3 times to remove extra air bubbles.
Bake the cake for 30 minutes in a preheated oven.
Let the cake to be fresh. The cake will shrink a little.
Lose the edges and unmold the cake.
Sprinkle powdered sugar and serve them with whipped cream or a cup of tea.