Preheat oven to 350° F
Combine chopped chocolate and butter. Add to bowl, and melt over a pot of water on low heat. Stirring constantly.
Whisk together egg yolks and 1/2 cup sugar until thick and has a pale yellow color.
Stir chocolate into the egg yolk mixture.
Separately whisk the egg whites until thick. Add the remaining 2 tablespoons of sugar and beat to a light meringue.
Fold the chocolate into the meringue.
Pour the batter into the ramekins. Bake for 30 minutes in a hot water bath until done. Insert a toothpick in the middle of the cake and if it comes out clean, it is done.
Transfer the ramekins to a cooling rack. Cool for 10 minutes.
Add powdered sugar or any toppings of your choice to the flourless chocolate cake.