Preheat oven 350°F. Lightly butter and flour four 6-inch round cake pans. Set aside.
In a medium bowl, sift together the flour, sugar, baking powder, and salt. Set aside.
4 cups cake flour, 2 cups granulated sugar, 1 tablespoon baking powder, 1 teaspoon kosher salt
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter until smooth, about 2 minutes. Add in the vanilla and egg whites.
1 cup unsalted butter, 1 teaspoon pure vanilla extract, 8 large egg whites
Use the whisk attachment and continue beating the mixture on medium speed for about 30-60 seconds, incorporating a small amount of air into the egg whites. (Don’t overmix until they are peaks, just add enough air for it to begin to slightly foam.)
Add the flour mixture and milk, continuously mixing on slow to medium speed. Be sure to scrape the sides of the bowl, to incorporate all of the dry ingredients.
1½ cups milk
Once the batter is smooth and creamy, evenly divide the batter evenly into the prepared cake pans.
Bake for 25-28 minutes, using a toothpick to check for doneness. Let the cakes cool in their pans for about five minutes and then remove from the pans to let them cool on a rack.
Before assembling, cut the tops off of each layer to have even and flat layers.
Wrap and freeze cakes for about 4-6 hours before frosting.( I have found this baker’s trick helps keep the crumble to a minimum when trying to frost a naked cake. Otherwise, the crumbs will get into the frosting and it won’t be as clean.)
To assemble the cake, add about ½ cup of frosting around the top of the first layer of cake, evenly spread over the top of the cake, allowing a small amount to go over the edges of the cake. Gently add the next cake layer, and gently press it into the bottom layer. Repeat with the next cake until all 4 layers are stacked with a layer of frosting in between each layer.
2 cups vanilla buttercream frosting
Using a flat spatula, gently spread the extra frosting that came out through the edges of the layers, to lightly coat the cake. You can adjust the thickness of the outer coating, depending on your preference and how “naked” you want your cake to look.
Top the cake with fresh flowers, a cake topper, of fresh fruit dipped in sugar.