Preheat the oven to 350°F. Spray a bundt pan with Baker's Joy which is a baking spray with flour in it. If that isn't available, use softened butter and a pastry brush to generously coat every crevice of your bundt pan. Add 2 tablespoons of flour and shake the pan to coat every surface before knocking out any excess flour.
Beat butter and sugar on medium high for about 3 minutes until creamy and light. Add vanilla and eggs, one at a time, mixing well and scraping the bottom and sides of the bowl.
2 cups granulated sugar, 1 cup salted butter, 4 large eggs, 3 teaspoons vanilla extract
With the mixer on low speed, add 1/3 of the flour, baking powder, baking soda, and salt. Mix just until combined. Then add 1/2 of the buttermilk, mixing again just until combined. Continue alternating adding remaining flour and buttermilk, mixing just until combined. Stop and scrape the bowl as needed.
3 cups all-purpose flour, 1 teaspoon baking powder, 1 teaspoon salt, 1 cup buttermilk, 1/2 teaspoon baking soda
Pour into the prepared pan and bake for 50-60 minutes. Check to see if the cake is done around the 50 minute mark. Insert a tooth pick or skewer into the thickest center part of the cake to test it. If it comes out wet, let the cake bake for a few minutes longer before checking again. When the tester poked into the center comes out clean with just a few crumbs clinging to it, it's done.
Combine butter, sugar, and water in a small saucepan set over medium heat to make the glaze. Let it heat to a simmer and cook until the butter melts and the sugar dissolves. After about 5 minutes, remove the slightly thickened butter sauce from the heat and stir in vanilla.
6 Tablespoons salted butter, 3/4 cup granulated sugar, 2 teaspoons vanilla extract, 1/4 cup water
With the warm cake still in the bundt pan, use a skewer to poke holes all over the cake. Slowly pour about 2/3 of the glaze over the top, letting it soak into the holes. It might seem like a lot of liquid, but the cake will soak it all up. Let it soak in for 30 minutes before inverting the pan on to a serving plate or cake stand. Brush the rest of the glaze over the outside of the cake using a pastry brush. Dust the cake with powdered sugar before serving.
Powdered sugar