¾cupunsalted butter, at room temperature (1 ½ sticks)
5eggs, at room temperature
1 ¼cupsbuttermilk, at room temperature
Chocolate Fudge Frosting
Combine sugar, milk, 2 tablespoon butter, Karo light corn syrup, salt and chocolate in a pot. Place over medium heat, until it comes to a boil. Boil for 6 minutes.
Remove pot from heat and drop in stick of butter. Let the butter melt and do not stir until fudge cools, about 1 hour.
Add vanilla extract once fudge is cool and beat with wooden spoon until it is thick and creamy, about 5-10 minutes.
Preheat oven to 350°F and prepare three 9" round cake pans. Line the bottoms with parchment paper and nonstick cooking spray.
In a medium bowl, whisk together the flour, baking powder and salt. Set aside.
In the bowl of a stand mixer, cream together the sugar, butter and oil until light and fluffy. Add the eggs one at a time and beat until mixed. Add the Greek yogurt and vanilla and beat until combined. You can also use a hand mixer to do this.
With a spatula and hand-mixing, add the dry ingredients to the wet ingredients, alternating with the buttermilk and ending with the flour until just combined. Do not over-mix.
Pour slightly less than 1 cup of batter into prepared cake pans. Bake for 10-12 minutes or until a toothpick inserted comes out clean. Allow to cool for a couple minutes and then carefully invert on a cooling rack.
Once the cake pans are cool, re-line with parchment paper and coat again with nonstick baking spray. Repeat baking with the remaining batter to make 9 thin cakes total. Allow all 9 layers to cool completely, about 45 minutes
Spoon about ¼ cup of frosting and spread to the edge of the first layer. Repeat with each layer and then spread the rest of the frosting on the top and sides of the cake.
Do not skip the buttermilk as it helps create the moistness you expect from cake. If you don’t have buttermilk you can make your own. Use whole milk mixed with ¼ teaspoon of white vinegar or fresh lemon juice instead of buttermilk. Fill a measuring cup with the lemon juice/vinegar then the rest with whole milk to reach ¼ cup + 2 tbsp.
If you don’t have Greek yogurt, you can either replace with sour cream.
All refrigerated items should be at room temperature, which helps the batter mix easily and evenly.
You may not realize this but baking powder actually expires pretty quickly. Use baking powder that is less than a year old since it has been opened. If you use older baking powder, it won’t be powerful enough to help leaven the cake. You can test it by stirring half a teaspoon of baking powder into a cup of hot water. It will immediately start to fizz and release carbon dioxide gas if it’s still fresh enough to use.
You know cake is done when you insert a toothpick in the center and it comes out clean.
Allow the cakes to completely cool before adding the frosting, otherwise it will melt.