Preheat oven to 325 degrees F (165 degrees C). Grease and flour one 10 inch bundt pan.
Cream together the white sugar and 1 cup of the butter. Add the eggs one at time, beating mixture well after each. Mix the baking soda with the buttermilk. Add to butter mixture and beat.
Sift flour three times before measuring. Add sifted flour and 1/4 teaspoon salt to the butter mixture. Stir in the 2 teaspoons vanilla. Pour batter into prepared pan.
Bake at 325 degrees F (165 degrees C) for one hour. Let cake cool and top with Caramel Icing.
To Make Caramel Icing: In a saucepan over medium heat cook the brown sugar, remaining 1/2 cup butter, and the evaporated milk. Stirring frequently bring mixture to a boil and let boil for 3 minutes. Remove from heat and stir in the 1 teaspoon vanilla, beat until thick. Pour over top of cooled bundt cake.
