Preheat oven to 350 degrees F (177 degrees C). Grease, or spray with a non-stick vegetable spray, a set of three 9 by 1 inch (23 x 2.54 cm) checkerboard cake pans, line with parchment paper, and then grease and flour again.  Set aside.

Melt the chocolate in a stainless steel bowl set over a saucepan of simmering water.  Set aside.

In a separate bowl whisk together the 4 large eggs, 1/3 cup (80 ml) of milk, and 1 tablespoon pure vanilla extract.  Set aside.

In the bowl of your electric mixer, combine the flour, sugar, baking powder and salt and beat to combine.  Add the butter and remaining 1 cup (240 ml) milk and beat on low speed until the dry ingredients are moistened.  Increase the speed to medium and beat for about 2 minutes.   Scrape down the sides.  Gradually add the egg mixture to the flour mixture  and beat to incorporate the ingredients.

Divide the batter in half, placing each in a separate bowl (in one of the bowls have a little more than half the batter).   Stir the melted chocolate into the smaller amount of batter until it is thoroughly combined.   Fill two large pastry bags, fitted with large round tips (about 3/4 inches (2 cm) in diameter, one  with the chocolate batter and the other with the white batter.

Place the divider rings in one of the prepared pans and pipe batter into each section, alternating batter colors (for example - outer and inner ring yellow, middle ring chocolate).  The batter should fill the pan about half full.  Using the back of a spoon, smooth the batter.  Now carefully lift out the divider.  Wash the divider before placing in the next pan.  When piping batter for the second layer, alternate the colors, i.e. if you started with yellow for the outside ring, start with the chocolate.  Pipe batter into the third pan exactly like the first pan. (Note:  You will end up with two pans having the same color pattern and one the opposite.)

Bake about 20 minutes or until a tester inserted near the center comes out clean and the cakes spring back when pressed lightly in the center.  The cakes should start to shrink from the sides of the pans only after removal from the oven.   Be sure that you do not overbake this cake or it will be dry. 

Let the cakes cool in the pans on a wire rack for about 10 minutes.  Loosen the sides with a knife or spatula and invert onto a greased wire rack.  To prevent splitting, reinvert so that the tops are up and cool completely before covering with Ganache.

Note:  When stacking the layers of the cake, make sure the bottom and top layer are the same pattern so you end up with the checkerboard pattern when you cut the cake.

Place one layer on a cake circle (top side of cake down on the cake circle so you get a nice flat top) and put on a wire rack.  Spread with a thin layer of ganache (you want a very thin layer of ganache so it does not interfere with the checkerboard pattern).  Place the second layer (top side down) on top of the first and spread with another thin layer of ganache.  Top with the last cake layer (top side down).  Pour the rest of the ganache on the top of the cake and with a spatula gently spread the ganache so it drips down the sides of the cake.  Use leftover ganache to cover any missed spots.  Once the ganache has set gently transfer the cake, using a large offset spatula, to a platter or cake stand.

Store 2 days at room temperature or 5 days refrigerated although this cake is best eaten the first day.

Adapted from Cake Bible by Rose Levy Beranbaum