Preheat the oven to 325 degrees F and grease & line two 6 inch cake pans with parchment paper.

In a large bowl, whisk together the cake flour, cocoa powders, baking powder, and salt. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter and sugar for 2-3 minutes until light & fluffy.

Mixing on low speed, add the eggs one a time. Scrape down the bowl and mix in the vanilla.

Add half of the dry ingredients and mix until just combined.

Mix in the sour cream and oil.

Add the rest of the dry ingredients and mix until just combined. Scrape down the bowl to ensure everything is evenly incorporated.

Divide the batter between the prepared cake pans and smooth out the tops with an offset spatula.

Bake the cakes for about 35-40 minutes or until the edges begin to pull away form the sides of the pan and a toothpick inserted comes out clean.

Turn the cakes out onto a wire rack to cool completely.

Chop the chocolate and add to a large bowl. Set aside.

In a small saucepan, heat the heavy cream over low heat and bring to a simmer or about 190 degrees F.

Pour the hot heavy cream over the chocolate, place a plate on top of the bowl, and allow to sit for a couple minutes.

Remove the plate and gently stir with a rubber spatula until the ganache is smooth. Alternatively, you can use an immersion blender.

Cover the bowl and allow to sit for 1 hour (but no longer!) at room temperature to thicken.

Place the first cake layer on a cake stand or plate. Use a 3 tablespoon cookie scoop to add 3 scoops of ganache to the first layer. Use an offset spatula to spread into an even layer. Place in the fridge to chill for about 10 minutes.

Place the second cake layer on top upside down. Add a few large dollops of ganache to the top of the cake, and use the offset spatula to smooth out the top, and spread the excess all over the sides. Continue decorating the cake as desired, and enjoy!