Preheat oven to 350 degrees F. In a large bowl cream together butter and sugar until light and fluffy, approximately 2-3 minutes. Add eggs, one at a time, beating well after each egg. Add in vanilla and mix to combine. Add one cup of flour, baking powder, baking soda and salt, and mix well. Add half of the buttermilk, mix well to combine. Add remaining flour and mix well to combine. Add remaining buttermilk and mix well to combine.