Preheat oven to 350°F (175°C). Grease and flour a 9-inch round cake pan.

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

In a large bowl, cream butter and brown sugar until light and fluffy. Add eggs one at a time, beating well after each. Mix in mashed bananas, sour cream, and vanilla.

Gradually add the dry ingredients to the wet mixture and stir until just combined. Fold in chopped pecans.

Pour batter into the prepared pan and smooth the top. Bake for 35–40 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool completely.

To make the caramel sauce, melt butter in a saucepan over medium heat. Add brown sugar and stir until dissolved. Stir in heavy cream, vanilla, and a pinch of salt. Let simmer for 2–3 minutes until thickened.

Drizzle the warm caramel sauce over the cooled cake. Top with extra pecans if desired. Slice and serve.