Louisiana Crunch Cake

    3 cups cake flour

    1 teaspoon salt

    1 teaspoon baking powder

    1/2 teaspoon baking soda

    2 cups granulated sugar

    1 cup butter, softened

    4 large eggs, room temperature

    1/4 cup sour cream

    1 cup buttermilk

    2 teaspoons pure vanilla extract

    1/4 cup granulated sugar

    1/4 cup sweetened flaked coconut