Preheat the oven to 350 degrees.  Grease a 9-inch spring form pan with butter and dust with flour.  Melt the chocolate with the butter in a double boiler, stirring occasionally  until the mixture is smooth.  Remove the chocolate from the heat.  In another bowl, beat the egg yolks together with the sugar and vanilla until thick (about 3 minutes).  In a third bowl, beat the egg whites with the salt until stiff (about 2 minutes).  Slowly and gently fold the chocolate into the egg yolk mixture., adding just a little chocolate at a time.  Fold in the egg whites.  Pour the batter into the spring form pan and bake until spongy (about 40 minutes).  Remove from the oven, remove form the spring form pan and place on a cake rack to cool.  Ice the cake and serve with whip cream and raspberries.

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Chocolate Icing.  Melt the chocolate with the cream in a double boiler, stirring constantly until smooth.  Don’t let it boil.  Drizzle over the chocolate cake.

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Whipped Cream.  Beat the cream using a hand mixer until the stiff.  Gently fold in the sugar and vanilla.