Preheat oven to 350°F. Generously butter and flour a 10-cup bundt cake pan* (see notes). Tap out excess flour. Set aside.
In a medium bowl, whisk together flour, salt, cinnamon, baking soda, and baking powder. Set side.
In the bowl of a stand mixer fitted with a paddle attachment (or using a handheld mixer), cream together butter, brown sugar, and sugar until smooth. Scrape down sides of bowl as needed.
On medium speed, add eggs one at a time, ensuring each egg is incorporated before adding the next. Add in vanilla.
Add dry flour mixture in three additions, alternating with the mashed bananas. Begin and end with the flour mixture. Mix on low speed until there are no longer any streaks of flour. Scrape down bowl as needed to ensure thorough mixing.
Transfer batter into prepared bundt cake pan. Level batter. Bake for 50-55 minutes until cake springs back to touch and toothpick inserted in cake comes out clean.
Cool cake in pan for 10 minutes. Invert bundt cake onto a wire rack. Remove cake from mold and cool to room temperature.