Preheat oven to 350°F. Grease 2 9-inch cake pans and line with parchment paper.
In a medium mixing bowl, sift together the cake flour, baking powder, baking soda, and salt. Set aside.
In a large mixing bowl or the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar on medium speed for 3-4 minutes until very light and fluffy.
Add the vanilla, then add the eggs one at a time, beating until smooth after each addition and scraping down the sides occasionally.
With the mixer on low, add the flour mixture in 3 additions, alternating with the buttermilk in 2 additions, beginning and ending with the flour, and mixing just until combined.
Divide the batter evenly between the 2 prepared cake pans, smoothing the top with a spatula.
Bake for 35-40 minutes until the edges are lightly golden, the center springs back when gently pressed, and a toothpick inserted in the center comes out with a few moist crumbs but no wet batter.
Remove from oven and let cool in the pan on a wire rack for 10 minutes.
Run a thin knife around the edge of the cakes, remove from pans, and return to the wire rack to cool completely before frosting, 45-60 minutes.