Preheat oven to Preheat oven to 350°F. Butter three 9 inch round cake pans, bottoms and sides, then sprinkle the pans with flour, then cut out parchment in circles to fit the bottom of the cake pans and place those in the pan.
Boil water and add espresso to it, stirring until dissolved.
Whisk cocoa powder, then buttermilk and vanilla into water/espresso mixture.
Sift flour, baking soda and salt into a separate bowl.
Using a stand mixer, whisk sugar and butter until fluffy. About 10 minutes.
Add each egg and the yolk, one at a time, into the butter mixture, letting each one fully mix into the batter before adding the next. Add in oil and mix until fully combined. The beat mixture on medium high speed for a minute- the mixture will be light and fluffy.
Fold in ½ of the flour and then fold in ½ of the buttermilk mixture to the batter. Then fold in remaining flour and then remaining buttermilk mixture.
Bake for 20-25 minutes or until a toothpick inserted comes out clean. Try baking the cakes on the same rack, or baking them one at a time. This will ensure even baking.
Once the cakes are done let them cool completely before decorating. While cakes are cooling make a double batch of my easy chocolate buttercream. Then frost and enjoy!