Directions

1. Grease two 9-inch cake pans, line with parchment paper rounds, then grease the parchment paper. Whisk the flour, baking soda, cocoa powder, and salt together in a large bowl. Set aside.
   
2. In a stand mixer fitted with whisk attachment add egg whites. Beat on high speed until fluffy peaks form, about 3 minutes. Transfer to a large bowl and set aside.
   
3. Using the stand mixer bowl switch to the paddle attachment. Add 1/2 cup butter and sugar together and beat on medium-high speed until combined, about 1 minute. Scrape down the sides. Preheat oven to 350°F.
   
4. Add the oil, egg yolks, 1 tablespoon vanilla extract, and vinegar and beat on high for 2 minutes. Scrape down the sides again. With the mixer on low speed, add the dry ingredients in 2-3 additions alternating with the buttermilk.
   
5. Beat in the food coloring just until combined. Gently fold egg whites into the cake batter. The batter will be silky and slightly thick. Divide batter between cake pans. Bake for 30-32 minutes or until the tops of the cakes spring back when gently touched and a toothpick inserted in the center comes out clean.
   
6. Remove cakes from the oven and cool completely in the pans set on a wire rack. The cakes must be completely cool before frosting and assembling.
   
7. In a bowl of a stand mixer fitted with a paddle attachment, beat the cream cheese and 12 tablespoons butter together on medium-high speed until smooth, about 2 minutes.
   
8. Add the powdered sugar, 1/2 tablespoon vanilla extract, and a pinch of salt. Beat on low speed for 30 seconds, then increase to high speed and beat for 3 minutes until completely combined and creamy. Frosting should be soft, but not runny.
   
9. Using a large serrated knife, slice a thin layer off the tops of the cakes to create a flat surface. Place one cake layer on your serving plate. Evenly cover the top with frosting. Top with second layer and spread remaining frosting all over the top and sides. Use an icing spatula and bench scraper for the frosting.
   
10. Refrigerate cake for at least 30-60 minutes before slicing. Cover leftover cake tightly and store in the refrigerator for 5 days. Frosted cake or unfrosted cake layers can be frozen up to 2-3 months. Thaw overnight in the refrigerator and bring to room temperature before decorating/serving.