Preheat the oven to 350°F. Spray a 9x5-inch loaf pan with a cooking spray (choose a cooking spray with the flour in it. I like Baker’s Joy brand) and set aside.
Make the cream cheese mixture. In a medium-sized bowl, beat together the cream cheese, sugar, sour cream, egg, flour, and vanilla. Set aside.
In another medium-sized bowl, mash the bananas and combine them with the sour cream. Set aside.
In a large bowl, with an electric mixer, cream together the butter and the sugar until it is fluffy, about 1 minute.
Add the egg and the vanilla and beat well.
In a separate bowl, whisk together the flour, baking soda, salt, and cinnamon.
Add the flour mixture to the creamed butter and sugar mixture, alternating with the mashed banana, blending well after each addition. Set aside.
Scoop half of the banana bread batter into the bottom of the prepared loaf pan, use a silicone spatula to spread it out evenly. Pour the filling mixture evenly over the top of the batter. Scoop the remaining batter over the top, using the spatula again to spread it out.
Bake for 1 hour 15 minutes, until a toothpick inserted in the center comes out clean.
Allow it to cool in the pan for 20 minutes before removing it to a wire rack to cool completely.