Whisk together in a medium mixing bowl, flour, baking powder, and salt; set aside.
Preheat oven to 325°F. Grease and flour a 12-cup bundt pan.
In the bowl of a stand-up mixer, beat butter on medium speed, until light and fluff, 6 minutes.
Gradually mix in sugar until blended. Beat on medium for 1 additional minute.
Add eggs, one at a time, mixing after each addition just until yolk disappears.
Reduce mixer speed to low. Add flour mixture and buttermilk, beginning and ending with flour mixture, on low speed until just combined. Scrape down bowl as needed. Mix in vanilla.
Pour batter into prepared bundt pan. Tap pan on the counter to remove any air bubbles.
Bake for 45 minutes in the preheated oven. Cover with foil and continue to bake, about 45 minutes longer, or until a wooden skewer inserted into the center comes out with just a few moist crumbs. Cool in pan on a wire rack for 1 hour. Remove from pan and cool completely on a wire rack.