Here's a recipe that I make whenever I'm recruited to make dessert for a dinner party. It's perfect for Passover since it contains no flour, but I bake it dozen months of the year. Preheat oven to 300 degrees. Generously butter an 8' springform and line the bottom with a circle of buttered wax paper. Melt chocolate and butter together and stir until smooth. Lightly whisk egg yolks, and gradually add chocolate mixture,mixing until blended.Add sugar,stirring once again until smooth. In another bowl, beat egg whites and salt until stiff. Fold a quarter of the egg whites into the chocolate mixture to lighten it, and then fold in the remainder. Turn batter into the pan, smooth the top slightly and bake for one and one half hours. Let cake stand at room temp until cool, then gently remove sides of springform and invert onto serving plate or paper lined cookie sheet if freezing.To serve, sprinkle with powdered sugar or frost with jelly and/or whipped cream,or light chocolate glaze. The cake will fall after removal from the oven. Don't worry,you're going to mask it with whipped cream. If you glaze it, do it on the bottom which will be perfect when inverted. This freezes perfectly so it's something you can make well ahead of time. After flash freezing it uncovered on a cookie sheet, wrap it securely. When ready to serve, put it on a serving plate while still frozen,and cover it well so that the condensation formed by defrosting will collect on the wrappings, and not on the cake. PS If a butter substitute is used, I don't guarantee good results. ----