Combine dry ingredients and sugar in mixer bowl; set aside.
Whisk together the eggs, vanilla, and buttermilk in large measuring cup; set aside.
Make batter using Reverse creaming method:
Start mixer on low speed. Add butter 1 TB at a time mixing constantly, until butter is incorporated into flour mixture. Should not be any large pieces of butter left. Mixture should appear yellowish and dry.
Add half of the egg/buttermilk mixture. Beat on low to medium speed until smooth but thick.
Add remaining egg mixture, beat about 15 seconds until smooth.
Divide batter between pans & spread evenly.
Bake at 350 on middle rack, until toothpick in center comes out clean, about 20 minutes.
Cool in pans for 10 minutes, remove and cool completely on racks.