Preheat your oven to 350°F (175°C). Grease and flour three 9-inch round cake pans.

In a medium bowl, whisk together flour, baking powder, baking soda, and salt.

In a large mixing bowl, beat the butter, granulated sugar, and brown sugar together until light and fluffy.

Add eggs one at a time, beating well after each addition.

Mix in the vanilla extract and mashed bananas.

Gradually add the flour mixture, alternating with the buttermilk, beginning and ending with the flour mixture.

Fold in the chopped pecans.

Divide the batter evenly among the prepared pans. Smooth the tops with a spatula.

Bake for 25-30 minutes, or until a toothpick inserted into the center of the cakes comes out clean.

Let the cakes cool in the pans for 10 minutes, then turn them out onto wire racks to cool completely.

Prepare Caramel

In a medium saucepan, melt the butter over medium heat.

Add the brown sugar and cream. Bring to a boil, stirring constantly. Remove from heat and let cool slightly.

Gradually beat in the powdered sugar and vanilla extract until smooth and creamy. If the frosting is too thick, add a little more cream until the desired consistency is reached.

Assemble dessert

Place one cake layer on a serving plate. Spread a generous amount of caramel frosting over the top. Repeat with the second and third layers.

Frost the sides of the cake with the remaining caramel frosting. Garnish with chopped pecans. Allow the frosting to set slightly before serving.