Vanilla Cake Layers:

• Preheat oven to 350°F / 175°C. Line four 7" or three 8" pans with parchment rounds, and grease with non-stick baking spray.
• Mix together 3 cups all purpose flour, 3 cups sugar, 2 1/2 tsp baking powder and 1 tsp salt in a stand mixer with a paddle attachment or hand mixer until fully combined.
• Mix in 1 cup of room temperature, unsalted butter slowly into the dry ingredients on a low speed. Continue to mix until no large chunks of butter remain and the mixture looks like moist sand.
• Pour in 1 cup of egg whites and mix on low until just incorporated. Mix in 1 1/2 cups buttermilk in two installments, on a low speed.
• Add in 2 Tbsp of vegetable oil and 2 tsp of vanilla extract and mix at a low speed until fully incorporated.
• If you plan to color your cake layers, add in the gel food coloring with the vanilla and oil.
• Scrape down the sides of the bowl with a rubber spatula, then beat on a medium speed for about 30 seconds to make sure everything is properly mixed together.
• Divide the batter evenly between your prepared pans. I like to use a scale to make sure each pan has the same amount of batter and will bake up to be the same height.
• Bake for 33-35 minutes or until a toothpick comes out with a few moist crumbs.
• Allow the pans to cool for 10 minutes, then run a small offset spatula around the perimeter of the pan to separate the cake from the pan.