16 tablespoons salted butter 9 ounces Dark Chocolate, coarsely chopped 6 eggs 3/4 cup granulated sugar 3/8 cup brown sugar 3/8 cup cake flour 3 tablespoons finely ground almonds 1/2 teaspoon cream of tartar
Preparation Preheat oven to 375 F.
Butter the sides and bottom of the pan. Line the bottom with parchment or waxed paper and flour the pan.
Melt the butter in a double boiler. Chop the chocolate into coarse pieces and add to the butter. Stir frequently until the chocolate is melted and smooth. It should not get much hotter than 115 degrees F. Set aside.
Separate the eggs and beat the sugars into the egg yolks until just mixed. While the chocolate is still warm, whisk the egg mixture into it, and then stir in the flour and the almonds. If the combined mixture has cooled, set it back over the bottom of the double boiler over low heat, stirring constantly, until it is barely warm.
Warm the egg whites slightly by swirling them in a bowl above a gas flame or over hot water (the whites will beat to a greater volume when warmed). Add the cream of tartar to the egg whites and beat until they look creamy and form rounded peaks. Spread the egg whites over the chocolate mixture and fold them together quickly without deflating the whites.
Pour into the prepared pan and bake for 30 to 40 minutes, or until the cake is completely set around the sides, but still has a soft and creamy circle, about 6 inches across, in the center. The cake will rise and crack around the edge and separate from the softer center. The center should wiggle just slightly when you shake the pan gently.
Set the pan on a rack to cool completely before unmolding.
To serve the cake, turn it out of the pan, peel the paper off the bottom, and drizzle with chocolate glaze or sprinkle lightly with powdered sugar. The cake keeps very well, if not iced, for three or four days. Just cover the pan with foil and keep at room temperature until ready to use.