Pre-heat oven to 350F. Grease three 7-inch round cake pans (or whatever shape pan you want to use). Add a layer of parchment paper on the bottom.
Mix flour, baking powder, baking soda, and salt in a medium sized bowl. Set aside.
Use a stand mixer with a whisk attachment to whisk the room temperature butter, sugar and vanilla extract till smooth and creamy. About 8 minutes. Make sure you stop the mixer halfway and scrape down the sides.
One at a time, add the eggs and mix well before adding the next egg. Beat till fully blended.
Remove the bowl from the mixer and using a spatula gently fold in 1/3 of the flour. Add 1/2 of the buttermilk and again fold in. Add 1/3 of the flour. Gently fold in till just mixed, add the remaining butter milk and gently fold in. Add the remaining flour and gently fold in. Do not over mix. You will end up with a slightly lumpy looking batter, but it should not have any dry pockets of flour.
Gently pour in 1/3 of the batter into each cake pan. Give the cake pan a gentle tap on the counter to release any trapped air bubbles and place in the oven.
Bake for 30-35 minutes until the tops are firm and bounce back when gently pressed, and a toothpick comes out clean when inserted into the cake.
Let them cool in the pan for 10 minutes before turning them out onto a baking rack to cook completely. Ideally overnight.