Preheat the oven to 350 degrees and grease a bundt pan with baking spray.
In a large bowl, cream butter until light and fluffy, about 1 minute. Add in granulated sugar and brown sugar, and beat until well combined. Add in eggs, 1 at a time, beating well after each addition. Set aside.
In a separate bowl, sift together flour, baking soda, cinnamon and salt. Slowly incorporate the dry ingredients into the wet, mixing until just combined.
Add in mashed bananas, sour cream, and vanilla extract. Mix until combined.
Pour batter into the bundt pan and bake for 45-50 minutes, or until the cake is golden brown and cake tester comes out clean.