Important Things To Note Before You Start1. Bring all your ingredients to room temperature or even a little warm (eggs, buttermilk, butter, etc) to ensure your batter does not break or curdle. 2. Use a scale to weigh your ingredients (including liquids) unless otherwise instructed (Tablespoons, teaspoons, pinch etc). Metric measurements are available in the recipe card. Scaled ingredients are much more accurate than using cups and help ensure the success of your recipe. 3. Practice Mise en Place (everything in it's place). Measure out your ingredients ahead of time and have them ready before you start mixing to reduce the chances of accidentally leaving something out.4. Chill your cakes before frosting and filling. You can cover a frosted and chilled cake in fondant if you wish. This cake is also great for stacking. I always keep my cakes chilled in the refrigerator before delivery for easy transporting. Preheat your oven to 335º F/168º C Prepare your cake pans with cake goop or another pan release. For square pans or cakes over 12", I also use parchment paper.
Combine the 4oz of buttermilk with the oil and set aside.
To the remaining 6oz of buttermilk, add your eggs, lemon zest, lemon extract, and lemon juice. Whisk lightly to break up the eggs and set aside.
Place cake flour, sugar, salt, baking powder, and baking soda into the bowl of your stand mixer with the paddle attachment attached.
Turn the mixer onto the lowest speed. Add in your softened butter in small chunks mix until the flour mixture resembles coarse sand.
Add your oil/milk mixture all at once to the dry ingredients and mix on medium (speed 4 on KitchenAid) for 2 full minutes to develop the cake's structure.
Scrape the bowl. This is an important step. If you skip it, you will have hard lumps of flour and unmixed ingredients in your batter. If you do it later, they will not mix in fully.
Slowly add in the milk/egg mixture in 3 parts, letting the batter mix for 10 seconds between additions. Stop to scrape the bowl once more halfway through. Your batter should be thick and not separated. If it is separated, some of your ingredients could have been too cold or you added your liquids too quickly.
Fill your cake pans 3/4 full with cake batter. Give the pan a little tap on each side to level out the batter and get rid of any air bubbles. You can also weigh your cake pans to ensure that each pan has the same amount of cake batter.
Smaller cakes will bake faster than larger cakes. Start with 30 minutes for 6" or 8" cakes and add time as needed. Each oven is different so adjust your baking time as needed. Cakes are baked when a toothpick comes out cleanly from the center. Remove cakes from the oven and give them a tap on the countertop to release air and prevent too much shrinking.
After cakes have cooled for 10 minutes or the pans are cool enough to touch, flip the cakes over onto a cooling rack and let cool until barely warm. Wrap your cakes in plastic wrap and chill in the refrigerator before frosting so they are easier to handle. You can also put them in the freezer if you are in a hurry for them to cool down.
Once the cakes are chilled you can now trim, fill and decorate your cake as you wish.