Preheat the oven to a temperature of 350°F (177ºC). Generously grease a bundt pan with butter or oil and set aside. Using an electric hand mixer, cream together the softened butter, vanilla extract and sugar in a large bowl until light and fluffy.
In another bowl, whisk together baking powder, baking soda, cake flour, and salt. Alternate adding the dry ingredients to the butter mixture and buttermilk, starting and finishing with the flour blend.
Drop in the eggs one at a time, blending just until incorporated after each addition. Pour the batter into the prepped pan and bake for 35-40 minutes or until a toothpick inserted into the center comes out clean.
Let the cake rest in the pan for 10 minutes before flipping onto a cooling rack. To make the glaze, melt butter and sugar together in a medium saucepan over low heat. Increase the temperature to bring the mixture to a gentle boil and let it simmer for about 3 minutes, stirring continuously.
Turn off the heat and add vanilla extract and water, stirring until amalgamated. drizzle the glaze over the cake and allow to cool completely before serving.