Start with preheating the conventional oven to 350 degrees. Afterward, lightly grease your 9-inch round cake pans with a little bit of butter. Then, line the bottom of your 9-inch pans with round parchment paper. Also, grease the parchment with butter. And make sure to set them aside.
Afterward, place the separated yolks in a small bowl and the egg whites in a large mixing bowl. Then, add the four egg whites to the mixing bowl. In addition to that, beat the egg whites using an electric mixer. Also, ensure to beat until you see stiff peaks. And be sure to set them aside.
Four whole eggs that you must separate and four egg whites at room temperature
After that, beat the butter and sugar in a different mixing bowl using an electric mixer. Also, beat for about six minutes. Likewise, you can do so until the butter mixture becomes light and fluffy. Besides that, scrape the bowl's sides and bottom throughout the process. Doing so mixes it evenly.
1 1/2 cups of butter at room temperature, about 12 ounces or 340 grams, 2 1/2 cups of sugar, about 550 grams
Next, add two pieces of egg yolks to the butter mixture. Then, beat for about twenty seconds or until well combined. Also, add the other two yolks. After that, beat for another twenty seconds until incorporated.
Four whole eggs that you must separate and four egg whites at room temperature
Afterward, combine and whisk your flour, baking powder, baking soda, and salt into a different mixing bowl.
3 cups of cake flour, about 390 grams, 2 tsp of baking powder, about 8 grams, 1/4 tsp of baking soda, about 1.2 grams, 1 tsp of table salt, about 6 grams or 1 1/2 tsp of Kosher salt, about 9 grams
Then, stir your champagne, buttermilk, and vanilla in a small bowl. Also, utilize your mixer to combine the dry ingredients with your wet ingredients at a low speed. In addition to that, alternate adding the liquid in four additions. With this, starting and ending with the flour mixture. After that, beat in low-medium speed. In that regard, carefully incorporate each addition in the mixture. Afterward, scrape the mixing bowl's sides and bottom using a rubber spatula to mix properly.
1/2 cup of champagne at room temperature, about 120 ml, 1/2 cup of buttermilk kept at room temperature, about 120 ml, 1 tsp of pure vanilla extract
Afterward, gently fold your egg whites into your champagne cake batter using a rubber spatula. Then, fold until incorporated. In addition to that, avoid over mixing.
Then, pour your champagne cake batter into your greased and lined 9-inch pans. Also, bake them for about thirty to forty minutes until cooked thoroughly. As a result, the cakes will be golden brown in color.
Finally, allow the cakes to cool in the pans for about five minutes. It is crucial to do this before turning them into a cooling wire rack to cool completely.