Preheat oven to 325 degrees F. Liberally grease and flour a large bundt pan and set aside.
In the bowl of a stand mixer, cream together the butter and sugar until blended. Add in the eggs one at a time, then the vanilla. Add in the salt, baking powder, and baking soda, then add the flour and buttermilk, alternating after each addition until a thick batter has formed.
Spread the batter evenly into the prepared pan. Bake for approx. 60 minutes or until a toothpick inserted near the center comes out clean. Cool for about 15 minutes.
While cake partially cools, make the butter sauce. In a small saucepan, combine all the butter sauce ingredients. Heat until bubbles just begin to show up around the edges of the pan. Remove from heat. Poke holes all over the surface of the cake and down into the cake, careful not to puncture all the way through. Pour the butter sauce evenly over the top of the cake and allow the cake to cool completely in the pan, allowing the butter sauce to set.
Once cake has completely cooled, invert onto a wire rack and dust with powdered sugar.