A flourless chocolate cake is a great time to let your inner chocolate snob shine through. Assuming you decide not to use any added sugar or flavorings, the only thing you’ll really taste in this cake is chocolate, so it makes sense to get finicky. This is one of those times the home baker has a tremendous advantage over the professional pastry chef, since even Jacques Torres, Mr. Chocolate himself, couldn’t afford to use the kind of top-quality chocolates you can. He’d never make a profit. So whip out your Garbo scarf and sunglasses and head out to the nearest gourmet shop.
The thing to remember when choosing chocolates for a flourless is that the more fat in the chocolate, the smoother and more pudding-like the cake. I therefore steer away from milk chocolates, since I like a nice firm stand-up slice on a plate. All bittersweet is the standard way to go, though I’ll frequently put in a proportion of extra-bittersweet for kick (about a third). I’ll even do all extra-bittersweet for a party of either serious chocoholics or Chinese immigrants (whom in my experience are not accustomed to sugary sweets and appreciate the harshness). Sweetness can be added after the fact by serving the cake in a puddle of some sort of sweet sauce…raspberry, crème anglaise, even chocolate. Of course the sugar can go right into your cake too if you wish, a quarter cup added to an all-bittersweet cake (with the 8 eggs) is a very satisfying middle ground.
But the what brand of chocolate is best? There I can’t help you, since that’s such a personal choice. Of the readily available high-end brands, Valrhona and Ghiradelli are excellent, as is Scharffen Berger if you dig their sort of rustic fruity-bitter aesthetic. Personally I like El Rey for flourless chocolate cakes. It’s a Venezuelan brand whose makers somehow manage to work a little of that South American rain forest authenticity into their flavor profile. I don’t know how they do it, but they do. Funny isn’t it that a country run by a socialist dictator should produce a chocolate called “The King”. My disdain for Hugo Chavez is almost enough to stop me from buying the stuff, though I’m fairly certain he doesn’t make it himself.