Preheat your oven to 325°.
Brush an even layer on the inside of you Bundt pan with melted butter. Add in a tablespoon of flour, turning and tapping the pan to coat. Tip any excess flour out of the pan and set aside.
In a medium bowl whisk together the flour, salt, baking powder and baking soda, then set aside.
In a large bowl, cream together butter and sugar until light and fluffy. Then add in all of eggs, buttermilk and vanilla. Mix until combined, scraping down the sides half way.
With the mixer on low, gradually add the dry ingredients into the buttermilk mixture, scraping down the sides and bottom of the bowl in between each addition. Mix until just combined, then use a spatula to mix in any last bit of flour.
Spoon the cake batter into your prepared Bundt pan.
Bake on the middle rack in your pre-heated oven for 50-60 minutes or until a cake tester comes out clean.
With 5 minutes left on your timer, prepare glaze by combining the sugar, butter, water and vanilla in a small sauce pan. Heat on low until melted, stirring occasionally. Do NOT bring to a boil.
Once the cake is baked, poke wholes while it's still warm. Spoon about half of the glaze all over, making sure the glaze seeps into the holes.
Let cake cool COMPLETELY before inverting the cake onto a plate or cake stand.
Once removed, re-heat glaze over low heat and brush over entire cake until there is no glaze left. Save any remaining glaze to pour over slices of cake.