1. For the Cake:2. Preheat oven to 350°F. Spray the bottoms of three 8-inch cake pans with non-stick spray and line with parchment.3. In a large bowl, sift together the cake flour, sugar, baking powder, and salt.4. In another large bowl, whisk together the eggs, egg whites, buttermilk, melted butter, oil, vanilla, and food coloring until smooth.5. Pour the wet ingredients into the dry ingredients and whisk *just until combined* (about 10-15 seconds). Do not overmix. A few lumps are fine.6. Divide the batter between the cake pans. Bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.7. Let cool in pans for 10 minutes, then invert onto a wire rack to cool completely.8. 9. For the Buttercream:10. In a stand mixer, beat the softened butter on medium speed for 4-5 minutes until very pale and fluffy.11. Add the powdered sugar, meringue powder, salt, and vanilla. Mix on low until combined.12. Increase speed to medium-high and beat for 4-5 minutes, scraping the bowl down.13. Add milk, 1 tbsp at a time, only if needed for a spreadable consistency.14. 15. For Assembly:16. Level the cooled cake layers. Place one layer on a cake stand.17. Frost with a layer of buttercream. Repeat stacking and filling all layers.18. Frost the cake all over with a thin crumb coat and chill for 30 minutes.19. Frost the cake with the remaining buttercream and decorate as desired.