Cut 8 (8-inch) rounds from wax or parchment paper, grease, and place on greased baking sheets.

Cream together 1 cup plus 2 tablespoons butter and 1 cup plus 2 tablespoons sugar until light and fluffy.

Beat in the eggs, one at a time, and stir in the vanilla extract.

Sift together twice the flour, cornstarch, and baking powder.

Fold the sifted dry ingredients into the butter mixture until just combined.

Divide the mixture into 8 equal portions.

Spread each portion thinly and evenly on a wax paper round, leaving a 1 1/2 inch border.

Bake at 375°F (190°C) for about 7 minutes, or until lightly tinted.

Carefully remove each cake layer from the baking sheet and let cool completely on a wire rack.

To make the filling, combine cocoa, cornstarch, and sugar in a mixing bowl.

Gradually add some of the milk to form a smooth paste.

In a saucepan, bring the remaining milk to a boil.

Add the cocoa mixture to the boiling milk and stir constantly over medium heat until thickened.

Remove from heat and let cool to lukewarm.

Soften butter and beat until creamy.

Gradually whip the butter into the cornstarch cream until smooth.

Let the filling cool completely.

Once the cake layers and filling are cooled, spread a layer of filling evenly over one cake layer.

Top with another cake layer and repeat until all layers are assembled.

Chill the cake well.

Melt the semisweet chocolate over hot water or in the microwave.

Pour the melted chocolate over the chilled cake, ensuring it is completely covered.

Decorate with rosettes of whipped cream and chocolate shavings.