Preheat the oven to 350°F (175°C). Grease a 9x5 inch loaf pan and line it with parchment paper, leaving some overhang on the sides.

In a large mixing bowl, beat the softened butter and brown sugar together using an electric mixer for 2 to 3 minutes until light and creamy.

Beat in the eggs one at a time, mixing well after each addition. Add the vanilla extract and mix until combined.

Add the mashed bananas and sour cream. Mix until combined.

In a separate bowl, whisk together the flour, baking soda, and salt.

Add the dry ingredients to the banana mixture and gently fold with a spatula until almost combined. Avoid overmixing.

Fold ½ cup of the chopped pecans into the batter, reserving the remaining ¼ cup for the topping.

Spoon half the banana bread batter into the prepared loaf pan. Drizzle half the ⅓ cup caramel sauce over the batter, keeping it slightly away from the edges.

Spoon the remaining banana bread batter over the caramel. Drizzle the remaining caramel sauce over the top and gently swirl using a butter knife, making 2 to 3 passes through the batter.

Bake for approximately 55 to 65 minutes. At the 45 minute mark, check the top of the bread for browning. If it is getting too dark, loosely cover the pan with aluminum foil and continue baking. Begin checking for doneness around 50 minutes. A skewer inserted into a section of bread without caramel should come out without wet batter.

Allow the banana bread to cool in the pan for 15 minutes before transferring it to a wire rack to cool completely.

If toasting the remaining pecans, add them to a dry skillet over medium-low heat and toast for 2 to 3 minutes, stirring frequently until fragrant. Remove from the heat and allow to cool.

Drizzle the remaining ¼ to ⅓ cup caramel sauce generously over the cooled banana bread, allowing some to run down the sides.

Sprinkle the reserved chopped pecans over the caramel while it is still sticky. Finish with a small pinch of flaky sea salt if desired.