01 - Preheat oven to 350°F. Grease and flour two 9-inch round cake pans or line with parchment paper.
02 - Whisk together flour, baking powder, baking soda, and salt in a medium bowl.
03 - Beat butter and sugar until light and fluffy, about 3 minutes, using an electric mixer.
04 - Incorporate eggs one at a time, beating well after each addition, then mix in vanilla extract.
05 - Alternately add the flour mixture and buttermilk to the butter mixture, starting and finishing with flour. Mix until just combined.
06 - Divide batter evenly between prepared cake pans and smooth the tops.
07 - Bake for 30 to 35 minutes or until a toothpick inserted in the center comes out clean.
08 - Allow cakes to cool in pans for 10 minutes, then transfer to wire racks to cool completely.
09 - Beat cream cheese and butter until smooth. Gradually incorporate powdered sugar until fluffy, then mix in vanilla and salt.
10 - Spread frosting over one cake layer, place the second layer on top, and frost the top and sides evenly.
11 - Slice into portions and serve immediately.