Start by preheating the oven to 325°F and adjusting the oven rack to the center position. Generously coat a 12-cup Bundt pan with a nonstick baking spray that includes flour, such as Pam with Flour or Baker’s Joy.

In a medium-sized bowl, whisk together the buttermilk, eggs, and vanilla extract. Set aside; it’s normal for the mixture to look slightly curdled as it sits.

In the large bowl of a stand mixer equipped with a paddle attachment, combine the flour, granulated sugar, baking powder, baking soda, and salt. Mix on low speed for about 30 seconds until evenly blended. Add the softened butter and pour in half of the buttermilk mixture. Mix on low until the ingredients are just combined and appear slightly crumbly.

Gradually stream in the remaining buttermilk mixture while keeping the mixer at low speed. Once all of the liquid has been incorporated, increase the mixer speed to medium and beat the batter for 3 minutes. Stop halfway through to scrape down the bowl with a rubber spatula, ensuring no unmixed flour remains. The batter should be smooth, creamy, and pale. Give the bowl another scrape-down to ensure thorough mixing.

Carefully pour the batter into the prepared Bundt pan, spreading it evenly. Bake for approximately 1 hour, or until a skewer inserted into the cake’s center emerges clean. Place the hot pan on a wire cooling rack. While the cake is still warm, use a wooden skewer or toothpick to poke around 40 holes into the base, penetrating about ¾ of the way through. Gradually spoon half of the prepared glaze over the cake, focusing on distributing it evenly. If the glaze begins to pool on the surface, add a few more holes to encourage absorption. Allow the cake to rest for 30 minutes.

Gently invert the Bundt pan onto a serving platter and lift it away. Brush or drizzle the remaining glaze over the top and sides of the cake, allowing it to soak in slowly for the best results. Take your time with this step so the cake absorbs as much glaze as possible. Let the cake sit for at least one hour before serving to ensure the flavors settle beautifully. Right before serving, lightly dust the top with confectioners' sugar using a fine mesh sieve.

In a small saucepan, combine the butter, granulated sugar, water, and vanilla extract. Set the saucepan over medium heat and bring the mixture to a gentle boil. Reduce the heat slightly and allow it to simmer for about 1 minute, or until the sugar has fully dissolved. Stir occasionally to ensure a smooth glaze. Remove from the heat and set aside.