Preheat oven to 350 degrees F. Grease a bundt pan with butter and dust with flour, cocoa powder, or turbinado sugar. Set aside.
In a medium bowl, combine flour, salt, baking powder, and baking soda and whisk.
In the bowl of a stand mixer fitted with a paddle attachment (or hand mixer), cream butter and sugars together until fluffy, about 2 minutes. Stir in mashed bananas and vanilla extract, then add eggs, one at a time, beating well after each addition.
On low speed, add half of the flour mixture, then buttermilk, then the other half of flour mixture, mixing until just incorporated, being careful not to overmix.
Pour batter into prepared bundt pan. Bake for 50-60 minutes, or until a toothpick inserted in the center comes out clean.
Cool cake completely in pan once it's done, then turn it out on to a serving platter.
Drizzle your desired amount of chocolate ganache over the cake and serve.
Notes
Store cake covered at room temperature. Is delicious served with its namesake ice cream. Will keep for 3-4 days, if it lasts that long!