Step 1 – Make the caramel topping
In a small saucepan, melt ⅓ cup butter over medium heat. Stir in the brown sugar and cook for 2–3 minutes until smooth and bubbling. Pour this mixture into the bottom of your greased cake pan.

Step 2 – Arrange the bananas
Carefully lay sliced bananas over the caramel in a single layer. You can use rounds or long strips for a more dramatic look. This will be the top of your cake once flipped.

Step 3 – Preheat oven and prep dry ingredients
Preheat your oven to 350°F (175°C). In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.

Step 4 – Mix the wet ingredients
In a large bowl, cream together softened butter and granulated sugar until light and fluffy (about 2–3 minutes). Add eggs one at a time, beating well after each. Mix in the vanilla, sour cream, milk, and mashed banana until combined.

Step 5 – Combine wet and dry ingredients
Gradually add the dry ingredients to the wet mixture. Stir just until combined—don’t overmix, or the cake can become dense.

Step 6 – Pour batter over bananas
Carefully spoon the batter over the banana-caramel layer in the pan. Smooth the top with a spatula.

Step 7 – Bake the cake
Bake for 45–50 minutes or until a toothpick inserted into the center comes out clean. The top should be golden brown and the edges slightly pulled away from the sides.

Step 8 – Cool and invert
Let the cake cool in the pan for 10–15 minutes. Run a knife around the edges, place a plate or cake stand over the top, and flip the cake carefully. Tap the pan to help release it.