Note: It is best to use fresh eggs. Separate the yolks and whites while cold for ease of separation. Cover the yolks with plastic wrap until you ready to use them.
Preheat oven 375 F
Butter 4 6oz ramekins and sprinkle with sugar.
Melt chocolate in a bowl over barely simmering water, stiring constantly, do not over heat chocolate. Once melted remove from heat, whisk in egg yolks briskly to incorporate.
In a mixing bowl beat egg whites with salt on medium high speed until they hold glossy soft peaks, continue beating egg whites on high speed, gradually adding the 1/3 cup of sugar, until egg whites hold stiff glossy peaks.
Gently fold 1/3 of the egg whites into chocolate mixture, then carefully fold in the rest egg whites until there are no white streaks in the mixture and the color is even.
Place ramekings on baking sheet. Spoon mixture into ramekins, allow to rest for 30 minutes or bake them right away, for 12-15 minutes until risen whith a crusty exterior.
Sprinkle with powdered sugar or top with whipped cream. Serve right away.