Preheat oven to 350�F. Line three eight-inch pans with parchment rounds, and grease with non-stick cooking spray.
Mix together all dry ingredients (flour, baking powder, sugar, and salt) in a stand mixer with a paddle until fully combined.
Mix chunks of room-temperature butter slowly into the dry mix, on a low speed. Continue to mix until no large chunks of butter remain, and the mixture becomes crumbly.
Pour in egg whites, and mix on low until just incorporated. Mix in the buttermilk in two installments, on a low speed. Add in vanilla and oil, and mix at a low speed until fully incorporated. Scrape down the sides of the bowl with a spatula, then beat on medium speed for about 30 seconds.
Add in a generous squirt of pink gel food coloring. Mix the batter on a low speed, scraping the sides and bottom of the bowl part way through to evenly color the batter.
Divide batter evenly between the prepared cake pans. I like to use a digital kitchen scale to weigh my pans, and ensure they all have the same amount of batter. This guarantees your layers will bake to be the same height.
Bake for 34-36 minutes (or until a skewer comes out clean). Allow to cool for 10 minutes, then run an offset spatula around perimeter of the pan to separate the cake from the pan.
Place cake layers into the freezer for 45 minutes, to accelerate the cooling process.
Once the cake layers are cooled. level the tops with a serrated knife.