Preheat your oven to 350°F (175°C). Grease and flour two 8-inch round cake pans. Line the bottoms with parchment paper circles.

In a large bowl, sift together the cake flour, granulated sugar, baking powder, and salt. Whisk briefly to ensure everything is well combined.

In the bowl of an electric stand mixer fitted with the paddle attachment (or using a hand mixer), cream the softened unsalted butter on medium speed until it is light and fluffy, about 2-3 minutes.

Gradually add about half of the dry ingredient mixture to the creamed butter, mixing on low speed until just combined. Scrape down the sides of the bowl.

In a separate medium bowl, lightly whisk the room temperature egg whites until they are just foamy. Gradually add the whisked egg whites to the butter-flour mixture in the stand mixer, mixing on low speed until just combined. Scrape down the bowl.

With the mixer on low speed, alternate adding the remaining dry ingredients and the room temperature whole milk to the batter. Start with a third of the dry ingredients, then half of the milk, then another third of the dry ingredients, the remaining milk, and finally the last third of the dry ingredients. Mix until just combined after each addition. Be careful not to overmix.

Stir in the pure vanilla extract until just incorporated.

Divide the batter evenly between the two prepared cake pans. Smooth the tops with a spatula.

Bake for 25-30 minutes, or until a wooden skewer or toothpick inserted into the center of the cakes comes out clean. The cakes should be lightly golden on top and spring back when gently touched.

Let the cakes cool in their pans on a wire rack for 10-15 minutes. Then, carefully invert the cakes onto the wire rack, remove the parchment paper, and allow them to cool completely before frosting and serving.