12 oz. Baker's semi-sweet chocolate or bitter sweet chocolate, broken into pieces
2/3 c. (5 oz.) unsalted butter
3/4 c. sugar
5 lg. eggs, separated
1/3 c. unbleached all purpose flour
1 tsp. unsalted butter for butter cake pan

Preheat the oven to 350 degrees. Combine the chocolate, sugar and butter in the top of a double boiler. Melt over medium heat, stirring until the ingredients are thoroughly blended. Allow the mixture to cool, then whisk in the egg yolks, then the flour.

Beat the egg whites in a large bowl just until they form firm peaks. Do not over beat. Add one third of the egg whites to the chocolate batter and mix it vigorously. Then gently fold in the remaining whites. Do this slowly and patiently. Do not over mix, but be sure that the mixture is well blended and that no streaks of the white remain.

Butter a 9 1/2" springform pan and pour in the batter. Bake until the cake is firm and springy, 35 to 40 minutes. Allow the cake to cool for several hours before unmolding. Serve with a dusting of powdered sugar, if desired. Serves 8. Very good.