Preheat the oven to 350°F. Line a 1.5lb loaf pan with parchment paper, leaving a little overhang for easy removal. Set aside.

Add the bananas to a large mixing bowl and mash with a fork until mostly smooth.

Add the granulated sugar, brown sugar, and vegetable oil to the mashed bananas. Whisk until well combined, then whisk in the eggs, vanilla extract, and vinegar until smooth.

Fold in the flour, baking powder, baking soda, salt, and cinnamon with a rubber spatula just until the dry ingredients are fully incorporated and no streaks of flour remain.

Pour the batter into the prepared loaf pan and spread it into an even layer. Bake for 50-60 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean or with just a few moist crumbs attached. If the top begins to brown too quickly, loosely tent it with aluminum foil during the last 10-15 minutes of baking.

Let the banana bread cool in the pan for 10 minutes. Carefully lift it out using the parchment paper and transfer it to a wire rack to cool completely before frosting.

Beat the softened butter and cream cheese together on medium-high speed for 2-3 minutes, or until smooth and creamy with no lumps.

Add the powdered sugar ½ cup at a time, mixing on low speed after each addition until incorporated.

Once all of the powdered sugar has been added, pour in the salted caramel sauce and beat until the frosting is light, fluffy, and evenly combined.

Spread the frosting over the cooled banana bread with an offset spatula or the back of a spoon. Drizzle more salted caramel over the top, swirl it into the frosting, and finish with a sprinkle of flaky salt before slicing and serving.