FOR THE CAKE

1. Preheat oven to 350 degrees. Line three 8-inch round cake pans with waxed or parchment paper. Butter the paper and the sides of each pan. Lightly sprinkle cocoa over the bottom and sides of each pan and set aside.
2. Add the butter to the bowl of a stand mixer fitted with the paddle attachment. Beat the butter on medium speed for about 1 minute until it’s fairly creamy.
3. Add the sugar, oil and vanilla extract. Beat the mixture on medium speed for about 5 minutes until the mixture is very light and fluffy looking and the sugar no longer feels real grainy. Stop about half way through and scrape down the sides of the bowl.
4. Add the eggs and egg yolks, one at a time, mixing well after each addition, to make sure it’s totally incorporated before adding the next one. Scrape down the sides of the bowl after each addition.
5. Reduce the mixer to low speed and add 1/3 of the dry ingredients, stopping to scrape down the sides and mixing just to incorporate. Add 1/2 of the buttermilk, mixing just until combined. Repeat with an additional 1/3 of the dry ingredients, followed by the second half of the buttermilk and finally the last 1/3 of the dry ingredients. Stop and scrape down the sides of the bowl and run your spatula under the paddle attachment. Give the paddle a couple of mixes and stop. It’s important to not over mix cake batter once you add the dry ingredients.
6. Divide the batter equally between the 3 prepared cake pans. Shake the pans gently, then use an offset spatula to finish smoothing out the tops. Tap each pan on a counter 2 to 3 times to remove any air bubbles.
7. Bake the cake layers until a toothpick test comes out clean, about 30 minutes. Allow the cakes to cool in the pans for 10 minutes. Run a knife around the edges and gently shake each pan up and down to ensure the cake is loose from all sides. Invert the cakes onto a wire rack to finish cooling.
8. If you’re not going to frost the cake layers until the next day, once they’re completely cooled, securely wrap them in plastic wrap and leave at room temperature.

FOR THE WHIPPED CHOCOLATE GANACHE

1. Add the whipping cream to a medium size microwavable bowl.  Heat the whipping cream in a microwave until it just begins to simmer.  There should be small bubbles forming around the edges.  Do not allow the cream to boil.
2. Add the chopped chocolate to the hot whipping cream.  Allow the mixture to sit without stirring for about 3 minutes.  Using a rubber spatula, slowly blend the chocolate into the cream until the chocolate has completely melted and is totally incorporated into the cream.  This will take 2 to 3 minutes.  I run the spatula across the underneath of the mixture and slowly come up the sides and into the middle, turning the spatula as I do.  When the chocolate and whipping cream are well combined the result will be a dark shiny chocolate mixture.  At this point you have now made chocolate ganache!  Now take it one step further and turn it into whipped chocolate ganache.  
3. Allow the chocolate ganache to completely cool.  I place it in the refrigerator to speed up the cooling process.  Refrigerate for 15 minutes.  Remove and stir it a few times with a spatula and return to the refrigerator.  Allow it to chill for 15 additional minutes and check it again.  Once the ganache is completely cool, transfer it to the mixing bowl of a stand mixture or hand mixer fitted with the whisk attachment.  Beat on medium-high speed until the ganache becomes light in color and thick and creamy.  It will also have more of a sheen instead of a glossy appearance.
4. Refrigerate until ready to use.  Gently mix the ganache a few times with a spatula before using.
5. Use the ganache to frost a two-layer cake or up to 24 cupcakes.  Refrigerate until about 30 minutes before serving.  Once the ganache sits out it will stay stable for several hours.  However, I don’t recommend leaving it out that long since it contains cream.