Creating this Banana Upside Down Cake is a straightforward process. Just follow these steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C). Prepare a 9-inch round cake pan by greasing it with butter.
2. Prepare Bananas: Slice the bananas into ½-inch thick rounds. Place them on the bottom of the prepared pan.
3. Make Caramel: In a small saucepan, melt the butter over medium heat. Stir in the brown sugar, mixing until combined and slightly bubbly. Pour this mixture evenly over the banana slices.
4. Mix Dry Ingredients: In a mixing bowl, whisk together the flour, granulated sugar, baking powder, baking soda, and salt.
5. Mix Wet Ingredients: In another bowl, beat the eggs, then add vanilla extract and buttermilk, mixing well.
6. Combine Mixtures: Gradually combine the wet and dry ingredients, stirring until just combined. Be careful not to overmix.
7. Pour Batter: Gently pour the batter over the banana and caramel layer in the cake pan, smoothing the top.
8. Bake: Place the pan in the preheated oven and bake for 40-45 minutes, or until a toothpick inserted into the center comes out clean.
9. Cool: Let the cake cool in the pan for about 10-15 minutes, then carefully invert the cake onto a serving plate.
10. Serve: Allow the cake to cool further before slicing and serving.

These steps ensure that your Banana Upside Down Cake turns out perfectly caramelized and incredibly moist!