Serves 8 to 10.

12 oz of bittersweet chocolate (preferably Lindt or Tobler)
2/3 cup of unsalted butter
3/4 cup of granulated sugar
5 large eggs, separated
1/3 cup of unbleached all-purpose flour
2 tsp of confectioner’s sugar for decoration

• Preheat oven to 350°F.
• Butter a 9-inch springform pan.
• Combine the chocolate, butter and granulated sugar in the top of a double boiler placed over simmering water.
• Melt over medium heat, stirring until the ingredients are blended.
• Set the mixture aside to cool.
• Whisk the egg yolks into the chocolate. Whisk in the flour.
• Beat the egg whites in a large bowl just until they form firm peaks; do not overbeat.
• Add one third of the egg whites to the chocolate batter and mix vigorously.
• Gently fold in the remaining whites. Do not overmix, but be sure no streaks of whites remain.
• Pour the batter into the prepared pan. Bake until cake is firm and springy, about 35 to 40 minutes.
• Cool on a rack for several hours before unmolding.
• This cake is traditionally served without icing. But, you may dust it with confectioner’s sugar for a finishing touch.