Step 1. Make the cake batter: Sift together all-purpose flour, salt, baking powder, and baking soda. In a liquid measuring cup, stir together buttermilk and vanilla extract.
Step 2. Cream butter and sugar: Beat butter and sugar until light and airy.
Step 3. Add eggs: Add eggs one at a time, beating to combine after each addition.
Step 4. Add remaining ingredients: Add flour and buttermilk mixtures alternately in three parts, beating to combine.
Step 5. Bake the cake: Spray to coat a Bundt pan. Pour in batter and bake until a wooden pick inserted in the center comes out clean.
Step 6. Prepare the glaze: Heat sugar, butter, and water in a saucepan until sugar dissolves. Stir in vanilla.
Step 7. Poke cake: Transfer cake pan to a wire rack. Use a skewer to poke deep holes all over the cake.
Step 8. Glaze the cake: Pour half of the glaze over the cake. Rest for 10 minutes.
Step 9. Top with remaining glaze: Loosen the sides of the cake, and invert onto a plate or platter. Warm remaining glaze and pour over the cake.
Step 10. Serve: Cool before serving.