Directions

1. Make the ganache: Place 2 ounces chocolate in a medium heatproof bowl. Pour cream into a small saucepan, and heat until bubbles appear around the edge. Pour the hot cream over the chocolate, let stand several minutes, and whisk until smooth. Pour the ganache into 6 squares of a plastic ice-cube tray. Freeze until solid.
2. Butter and flour six 6-ounce ramekins, and place on a parchment-lined baking sheet, taping out the excess flour; set aside.
3. Melt butter and the remaining 12 ounces chopped chocolate in a heatproof bowl over a pan of simmering water. Stir until smooth. Let cool slightly.
4. Meanwhile, in the bowl of an electric mixer fitted with the whisk attachment, combine the egg yolks, 1/4 cup plus 2 tablespoons sugar, and the vanilla. Beat until thick and pale yellow, about 5 minutes. Add the chocolate-butter mixture, and thoroughly combine. Fold in the ground almonds.
5. In a clean mixer bowl fitted with the whisk attachment, beat the egg whites on low speed until frothy, 2 to 3 minutes, then on medium-low until the whites are foamy and begin to thicken, just before soft peaks form. Gradually add the remaining 1/4 cup sugar, and beat until stiff peaks form. Stir one-third of the egg whites into the egg yolk–chocolate mixture to lighten it. Fold the remaining egg whites into the mixture. Spoon about 3 tablespoons of the batter into each ramekin. Removed the frozen ganache cubes from the freezer. (You may need to dip the bottom of the tray in hot water to get them out.) Place a cube in the center of each ramekin. Spoon the remaining batter into the ramekins, being careful to keep the ganache cubes in the center, and cover them completely. Freeze the filled ramekins until solid, about 1 hour.
6. Preheat the oven to 375 degrees with the rack in the center. Take the baking sheet from the freezer. Wrap any cakes to be saved, and replace in the freezer; leave the rest on the sheet. Bake until the batter has set, 20 to 25 minutes. Transfer the sheet to a wire rack to cool for 5 to 10 minutes. To unmold, cover one hand with a clean kitchen towel, and invert the cake into hand, removing ramekin, then invert again onto a serving plate, and dust with confectioners' sugar, if using. Serve hot.