Preheat oven to 350°F / 175°C. Line four, 7-inch or three 8-inch pans with parchment rounds and grease.

Mix cake flour, granulated sugar, baking powder, and fine salt together in a stand mixer or hand mixer until fully combined.

Slowly mix in unsalted butter into the dry ingredients on low speed until no large chunks of butter remain.

Pour in egg whites and mix on low until just incorporated. Scrape the sides and bottom of the bowl as needed.

Mix in buttermilk, vegetable oil, and vanilla extract on low speed until fully incorporated. Beat on medium speed for about 30 seconds.

For four, 7-inch layers, pour half of the batter into a separate bowl. Color one half light pink and the other deeper pink using gel food coloring. Divide evenly between prepared pans.

For three, 8-inch layers, pour 1/3 of the batter into a separate bowl. Color as above and divide between prepared pans.

Bake for 33-37 minutes or until a toothpick comes out with a few moist crumbs. Rotate pans halfway through baking.

Cool pans for 10 minutes, then run a small offset spatula around the perimeter of the pan to separate cake.

Place cake layers into the freezer for 30 minutes to accelerate cooling. Carefully remove layers from pans.

Level the tops and edges of the layers using a serrated knife.

While the layers cool, make the cream cheese buttercream frosting by beating unsalted butter and cream cheese until smooth.

Mix in vanilla extract and salt, then gradually mix in powdered sugar and heavy cream until desired consistency is reached.

Stack and frost cake layers on a greaseproof cake board, spreading an even layer of buttercream between each layer.

Add a thin coat of frosting around the cake to cover, chill until firm to the touch.

Add a thicker layer of frosting to smooth the sides of the cake.

Color remaining buttercream in three shades of pink, pipe hearts and dots around the cake.