Preheat oven to 400 degrees F. Butter and flour 6 ramekins, approx. 6 ounces each. 

In the top of a double boiler, over medium heat, melt the chocolate, butter, and cognac or brandy and stir until smooth. Set aside.

In a bowl, beat the sugar and egg yolks until ribboned and light colored. In another bowl, beat the egg whites until stiff. 

Gently fold the egg whites into the egg yolk mixture. Sift the flour over the top and fold flour and chocolate into the egg mixture. 

Spoon the mixture into the prepared ramekins, distributing evenly. Place the ramekins on a baking sheet and bake until the cakes have risen and the tops just begin to crack, 10 to 12 minutes.

Immediately remove the ramekins from the oven and run a knife around the edges of the ramekins. Gently invert each ramekin onto a dessert plate. Dust with confectioners' sugar and garnish with fresh raspberries. 

Serve warm with vanilla bean ice cream or whipped cream.