In a large mixing bowl, cream together the butter, brown sugar, and granulated sugar until light and fluffy.

Add the eggs one at a time, beating well after each addition.

In a separate bowl, whisk together the flour, baking soda, and salt.

Gradually add the dry ingredients to the creamed mixture alternately with buttermilk, starting and ending with the flour mixture.

Stir in the vanilla extract.

Pour the batter into a greased and floured 10-inch tube pan. Bake at 325°F for about 60 minutes or until a toothpick inserted into the center comes out clean.