Preheat oven to 350 degrees F. Carefully grease your bundt pan.

Whisk flour, baking soda and salt together. Set aside.

Add butter to the bowl of a stand mixer and mix until the butter is creamy. Add the sugar and beat until the butter/sugar mixture is pale in color and fluffy in texture. Add vanilla to the butter mixture. Add eggs (one at a time) and mix thoroughly after adding each egg--about one minute after adding each egg. Lower the speed of your mixer from medium to low an add mashed bananas. Then, add one half of the flour mixture and mix. Add the sour cream and mix to combine. Add the remainder of the flour to the batter. Mix until ingredients are combined.

Using a spatula, scrape the batter into your prepared bundt pan. Rap the bundt pan on your counter once or twice once all the batter is in the pan. This will remove any air bubbles from the batter.

Bake on the middle rack in the center of your oven at 350 degrees F. for 65 to 75 minutes. (Cover your cake loosely with tin foil for the last 15 minutes of baking.) Your cake will be done when a toothpick or wooden skewer comes out clean when inserted into the center of the cake.

Let cake cool on your counter and unmold onto your serving plate. Serve plain dusted with powdered sugar or drizzle a powdered sugar glaze (powdered sugar mixed with a little milk) onto the cake. You can serve this immediately or wrap it in plastic wrap and serve the next day. According to the original recipe, the texture of the cake improves when wrapped overnight and served the next day.