Preheat oven to 325°F. Lightly grease a 9-inch square baking pan, set aside.
In a large mixing bowl, whisk together the flour, salt, baking powder, baking soda and ¾ cup of granulated sugar. Make a well in the center.
In a medium mixing bowl whisk the eggs until blended. Add the sour cream, vanilla and milk. Whisk until blended. Slowly add the melted butter, while whisking to combine. Pour the sour cream mixture into the flour and sugar mixture. Stir with a spatula until the dry ingredients are moistened. The batter will be thick.