Preheat the oven to 325°F. Grease and flour a 10-inch Bundt pan.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.

In a large bowl, cream the butter and sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition.

Stir in the vanilla extract.

Gradually add the dry ingredients to the wet mixture, alternating with the buttermilk, starting and ending with the dry ingredients.

Pour the batter into the prepared Bundt pan and spread it evenly.

Bake for 60-70 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool in the pan for 10 minutes, then turn it out onto a wire rack.

In a saucepan, combine the sugar, butter, and water. Cook over medium heat until the sugar is dissolved and the mixture is well combined. Remove from heat and stir in the vanilla extract.

Poke holes all over the warm cake using a skewer or toothpick.

Slowly pour the butter sauce over the cake, allowing it to soak in.

Let the cake sit for at least 30 minutes before slicing and serving.