This isn't just chocolate cake, it's flourless chocolate cake. And it's not just flourless chocolate cake, it's the cake you will compare all other cakes to. After you have this cake, all other cakes (chocolate and otherwise) will pale in comparison. So bake at your own risk.
This is adapted from an Epicurious recipe. It is one of the few recipes in which I will specify brands, but the chocolate matters.
Chocolate Coated Chocolate Cake
serves 1-20 depending on the people
5 100 gram Lindt Excellence 70% Coaco bars
3 75 gram Cote d'Or "Noir et Noir" chocolate bars
3/4 c butter
12 Tblsp sugar
1/2 tsp vanilla
1/2 c cream
1/2 c corn syrup
Break 4 Lindt bars into pieces. Chop butter into pieces. Melt them together over low heat, stirring frequently. Allow to cool to lukewarm.
Separate the eggs. Beat the yolks with 6 Tbsp sugar until light and frothy. Add vanilla. Spoon in the melted chocolate and stir until smoothly incorporated.
Whip the egg whites into medium peaks, adding remaining sugar (6 Tblsp) gradually. Fold into chocolate mixture.
Pour into a greased spring-form or loose bottomed cake pan. Bake at 350 for about 50 minutes, or until a toothpick comes out with crumbs.
Alow the cake to cool; it will fall a bit. Release sides of the pan, flatten the cake to a consistent thickness, and invert onto a serving plate.
Chop remaining chocolate (1 Lindt bar and three Cote d'Or bars) finely. Simmer cream and corn syrup. Remove from heat. add chocolate and stir until it melts.
Spread the top and sides of the cake with about half the coating. Freeze cake for ten minutes to set the glaze, then coat with the rest of the chocolate. It's thick and makes nice swirls.
Allow to chilled for about 2 hours. Serve at room temperature.