Creating the Banana Upside Down Cake is a straightforward process when you follow these simple steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C). Grease a 9-inch round cake pan.
2. Prepare Bananas: Peel and slice the bananas into thick circles. Set aside.
3. Make Caramel Mixture: In a small saucepan, melt the unsalted butter and brown sugar together over medium heat, stirring until well combined. Pour this mixture into the prepared cake pan.
4. Arrange Bananas: Place the banana slices evenly over the caramel mixture, arranging them to cover the entire bottom of the pan.
5. Mix Dry Ingredients: In a separate bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
6. Beat Wet Ingredients: In a large bowl, cream the granulated sugar and room temperature butter together until light and fluffy. Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.
7. Combine Ingredients: Gradually add the dry mixture to the wet ingredients, alternating with the buttermilk. Begin and end with the dry ingredients, mixing until just combined.
8. Pour Batter: Carefully pour the batter over the arranged bananas in the cake pan, smoothing the top with a spatula.
9. Bake: Place the cake in the preheated oven and bake for 40-45 minutes or until a toothpick inserted into the center comes out clean.
10. Cool: Once baked, remove from the oven and let it cool in the pan for about 10-15 minutes. Then, carefully invert the cake onto a serving plate and let it cool completely.

This step-by-step process will guide you in creating a beautiful and tasty Banana Upside Down Cake.