Preheat the oven to 325 degrees and spray a Bundt pan with baking spray. (Or grease with butter and dust with flour, shaking out the excess)
In a medium bowl, whisk together the flour, baking powder, salt and baking soda. Set aside.
In the bowl of a stand mixer, beat the butter and sugar together until light and fluffy. Add in the eggs one at a time, followed by the whiskey and vanilla.
Add in half of the flour mixture and half of the buttermilk and mix until combined. Add in the remaining half of the flour and buttermilk, mixing until no lumps of flour remain.
Pour the batter into the prepared Bundt pan and bake for 1 hour and 5 minutes or until a toothpick inserted in the center comes out clean.
Leave cake in pan and place on a wire rack.
Add the butter and sugar to a saucepan over medium heat and whisk until butter has melted. Do not boil! Remove from the heat and stir in the whiskey and vanilla. Pour the mixture over the cake.
Allow cake to cool in the pan for 30 minutes to an hour. Place a plate on top of the pan and flip over, inverting the cake onto the plate.
Slice into pieces and serve.