Preheat oven to 350 degrees F (177 degrees C) and place rack in center of oven.  Butter and flour an 9-inch heart-shaped cake pan (with 2 inch (5 cm) sides).

For the Chocolate Cake:  Separate the eggs, placing the whites in one bowl and the yolks in another.  To the whites, add the extra egg white and then cover both bowls with plastic wrap.  Bring them to room temperature (about 30 minutes) before using.

Meanwhile sift together 2/3 cup (130 grams) granulated white sugar, flour, cocoa powder, baking powder, baking soda, and salt.  Set aside.

In a liquid measuring cup, whisk together the oil, water, and vanilla extract.

In your electric mixer beat the egg yolks for a minute or two on high speed.  Turn the mixer on low speed and slowly pour the oil mixture into the egg yolks until very well combined.  Gradually add the flour mixture and beat until well incorporated.

In a separate mixing bowl, with the whisk attachment, beat the egg whites until foamy.  Add the cream of tartar and continue to beat until soft peaks form.  Gradually beat in the remaining 1/3 cup (65 grams) of sugar and beat until stiff peaks form.  With a large rubber spatula or wire whisk, gently fold the egg whites into the batter just until blended (being careful not to deflate the batter). 

Pour the batter into the prepared pan and bake for about 30 to 35 minutes, or until a wooden skewer inserted into the center of the cake comes out clean.  (When lightly pressed the cake will spring back).  Cool on a wire rack.  To remove the cake from the pan, run a sharp knife around the inside of the pan to loosen the cake.  Invert onto a wire rack. 

For Chocolate Whipped Cream:   In a large mixing bowl combine the whipping cream, vanilla extract, sugar, and cocoa powder.  Cover and chill the bowl and beaters in the refrigerator for at least 30 minutes, preferably an hour, so the cocoa powder has time to dissolve.  Beat the mixture until stiff peaks form.

To Assemble the Cake:  Once the Chocolate Chiffon Cake has cooled completely, place on a flat surface and, using a serrated knife, cut the cake, horizontally, into two layers.  Turn over the top layer of the cake (so the top of the cake becomes the bottom) and spread with the chocolate whipped cream.  Place the second layer of cake, cut-side down, on top of the chocolate cream, gently pressing to compact.  Cover with plastic wrap and place the cake in the refrigerator for several hours, or even overnight, before covering with the ganache.

For the Ganache:  Place the chopped chocolate in a medium sized stainless steel bowl.  Set aside.  Heat the cream and butter in a small saucepan over medium heat.  Bring just to a boil.  Immediately pour the boiling cream over the chocolate and allow to stand for a few minutes so the chocolate melts.  Gently stir with a whisk until smooth.  Add the liqueur, if using.

To Cover the Cake with the Ganache:  Put the cake on a wire rack that is placed over a baking sheet.   In this way if the ganache drips it will end up on the baking sheet, which makes clean up easier.  Pour the ganache onto the center of the cake and, with a large spatula, spread the ganache over the top of the cake, using big strokes to push the ganache over the sides of the cake, to create an even coating of ganache.   If there are any bare spots on the sides of the cake, cover with some of the ganache that has accumulated on the baking sheet.  (If there is leftover ganache, strain to remove any crumbs and use to make truffles.)

Gently transfer the cake to your serving platter and place the cake in the refrigerator until serving time.  This cake can be made a day or two before serving.  Decorate the top of the cake with fresh raspberries, if desired.  Raspberry Sauce would also make a nice accompaniment to this dessert.

 Serves 8