Grease a 9x13 inch rectangle baking pan and coat with baking spray. Then line the bottom with parchment paper. Set aside while you work on the caramel.

For the caramel sauce topping, in a small pot over medium heat, add in the butter, brown sugar, and rum. Cook until the butter has melted and the sugar has dissolved.

Bring the sauce to a simmer and cook for about 2-5 minutes until darkened slightly.

Remove the pan from the heat and pour the sauce into your prepared baking pan. Quickly spread the sauce evenly using an offset spatula as best as you can.

Peel and cut your semi-rip bananas in half lengthwise and lay them on top of the caramel with the cut side down. Set aside while you work on the banana cake batter.

Preheat the oven to 350°F.

For the banana cake batter, in a bowl, combine the flour, baking powder, cinnamon, and salt. Set the dry ingredients aside.

In a large bowl, add in the melted butter, brown sugar, mashed bananas, eggs, yogurt, rum, and the vanilla extract. Whisk to combine until smooth.

Gently fold in the dry ingredients until everything is smooth and combined.

Pour the batter over top of the prepared baking pan. Spread it out evenly using an offset spatula.

Bake for about 35-40 minutes or until a toothpick inserted into the center comes out clean.

Cool off for about 15 minutes. Carefully release the cake and flip it over. Lift the pan off to reveal the stunning upside down cake.

Slice and serve warm with a scoop of vanilla bean ice cream if desired!