Preheat the oven to 325°F. Butter and flour a 10- to 12-cup Bundt pan.

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

In a large mixing bowl or using a stand mixer with a paddle attachment, beat the butter and sugar at medium speed until fluffy, about 3 to 4 minutes, occasionally scraping the sides of the bowl.

With the mixer on low, add the eggs one at a time, beating well after each addition.

Gradually add the flour mixture to the butter mixture alternately with the milk, starting and ending with the flour mixture, and beating just until combined after each addition.

Spoon the batter into the prepared pan.

Bake for 1 hour or until a wooden pick inserted near the center comes out clean.

As soon as the cake is out of the oven, in a small saucepan, combine the butter, sugar, and water. Bring to a simmer over medium heat, stirring constantly. Continue stirring until opaque and slightly thickened, approximately 2 minutes. Remove from heat, then stir in the vanilla.

Pour the mixture over the cake in the pan. Allow it to cool for 15 minutes. Then, invert the cake onto a wire rack and let it cool completely before serving. Store the cooled cake covered at room temperature for up to 5 days.