Preheat the oven to 350F and grease three 6” round pans or two 8” round pans.
In a large bowl, sift together the flour, cornstarch, sugar, baking powder, and salt. Set aside.
Whisk the eggs, milk, and vanilla together until combined.
Add the softened butter to the wet ingredients 2 tablespoons at a time. Use a stand mixer fitted with the whisk attachment or a handheld mixer to beat until just combined. The mixture will appear sandy.
Add half the wet ingredients to the dry ingredients and beat until just combined. Add the remaining wet ingredients and beat until smooth. Be careful not to over mix.
Pour the batter evenly into the pans and bake for 20-25 minutes or until a toothpick inserted in the center comes out clean.
Let cakes cool completely before frosting.