French Chocolate Cake - cooking recipe

Ingredients

3/4 superfine sugar, plus some for sprinkling
10 oz dark chocolate
3/4 unsalted butter
2 t vanilla
5 eggs, separated
1/4 cup flour, sifted
pinch salt
10x sugar for dusting

Preparation

Preheat the oven to 325 degrees. Generously butter a 9 1/2 inch springform pan and sprinkle with sugar, tapping out excess.
Set aside 3 T sugar. Place chocolate, butter and remaining sugar in a heavy saucepan and cook over low heat until the chocolate and butter have melted and the sugar has dissolved. Remove the pan from heat, stir in vanilla and cool slightly. Beat in egg yolks, beating well after each addition. Stir in flour.
Beat egg whites in mixer until frothy. Add salt and beat to soft peaks. Add the reserved sugar and beat to stiff, glossy peaks. Add 1/3 of the egg whites to the chocolate and mix to lighten. Fold in remaining egg whites.
Pour into prepared pan and tap gently to release any air bubbles. Bake for 35-45 minutes until well risen and the center springs back when lightly touched. Transfer cake to a wire rack and remove the side of the pan. Cool completely. Remove bottom and dust with 10x sugar.