Grease and flour two 9-inch round cake pans, or one 9x13-inch baking pan, or 24 to 30 cupcake wells with paper liners. Set aside.
In a large bowl, sift together flour, baking powder, baking soda and salt.
Using an electric mixer, cream butter and sugar together on medium speed until light and fluffy.
Add eggs one at a time, beating after each addition. Add vanilla and scrape down the sides of the bowl.
Add flour mixture 1 cup at a time, alternating with the buttermilk until all is combined. Do not over mix the batter, just enough to remove all the lumps.
Pour the batter into prepared pans and rap the pans on the counter a couple of times to remove air bubbles.
Bake round cake pans at 350 degrees for 30 to 40 minutes. The 9x13 pan for 35 to 45 minutes or until a toothpick comes out clean. The cupcake tins for about 20 to 25 minutes or until the top of the cupcakes spring back when lightly touched.
Cool round cakes for 10 minutes before loosening, then carefully turn out the cake onto a sugar dusted piece of parchment paper, and allow to finish cooling on the wire rack.
Cool 9x13 pan and cupcake tins completely on wire racks before frosting.