Preheat the oven to 325°F. Spray and line 3, 9 or 8-inch cake pans with parchment.

Sift together cake flour, cornstarch, baking powder, and salt. Set aside.

In the bowl of a stand mixer fitted with the whisk attachment or in a large mixing bowl with an electric mixer, begin whisking the egg whites on medium low with the cream of tartar. Once the whites become frothy, begin adding the smaller portion of sugar by the teaspoon.

Turn up the mixer to high and beat until stiff peaks form. Being careful not to over whip or they will be difficult to incorporate into the batter and, thus, defeating the purpose!

Remove meringue from the mixer bowl and transfer to a clean bowl (or switch to a second mixer bowl if you have one! Lucky!)

Don’t stress about any meringue that remains behind. Add the butter and sugar to the bowl. Switch to the paddle attachment and cream the butter and sugar until light and fluffy. This will take at least 5 minutes depending on your mixer. It will also depend on how soft your butter was before mixing. The softer, the faster.

Beat in extracts. With the mixer on low, alternately add the flour mixture and the milk. I never allow the flour mixture to mix in completely before adding the next round. This helps prevent overmixing.

Remove the mixer bowl from the machine, scrape down the paddle attachment. Fold in any remaining dry ingredients.

Take about ¼ of the meringue and aggressively fold it into the batter. This is called “sacrificing” because you are sacrificing the aeration in the meringue to loosen the batter. Fold in the remaining meringue in 2-3 additions; being careful not to over fold.

Portion between the prepared cake pans. Spread out batter evenly with an offset spatula.

Bake in the preheated oven for 14-18 minutes or until a cake tester or toothpick comes out from the center with only clinging crumbs.

Cool 10 minutes in pans before flipping out onto a wire rack to cool completely.

Place the bottom layer on a cake stand or plate. Add about ½ cup frosting to the top and smooth out. Add the second layer and repeat with another ½ cup of frosting and the top layer. Flipping this last layer over so the bottom of the cake is now the top. This allows for a completely flat cake.

Chill cake for about 30 minutes before frosting the outside.