Weigh out the ingredients
You'll need flour, cocoa powder, sugar, baking powder, salt, oil, butter, eggs, vanilla, and sour cream.
Combine dry ingredients
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.
Cream butter & sugars
Mixing on low speed, add the eggs one a time. Scrape down the bowl and mix in the vanilla.
Mix in eggs & 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.
Alternate dry & wet ingredients
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.
Allow cakes to cool
Heat the heavy cream over low heat and bring to a simmer. Pour the hot heavy cream over the chocolate. Gently stir with a rubber spatula until the ganache is smooth. Cover the bowl and allow to sit for 1 hour (but no longer!) at room temperature to thicken.
Make the ganache
Decorate the cake as desired.
Enjoy this chocolate fudge cake for a special occasion or just because!