Preheat the oven to a temperature of 350 degrees Fahrenheit (175 degrees Celsius). Prepare a 9x5-inch baking dish by greasing it thoroughly to prevent sticking.

In a medium-sized mixing bowl, combine the flour, baking soda, ground cinnamon, and fine salt. Whisk them together to ensure uniform distribution. Set this dry mixture aside for later use.

In a separate, larger mixing bowl, cream together the packed brown sugar and unsalted butter until the mixture achieves a smooth consistency. Following this, incorporate the eggs into the mixture, ensuring to add them one at a time whilst mixing continuously.

Into the same bowl, incorporate the sour cream, mashed bananas, and pure vanilla extract. Mix thoroughly until well combined.

Gradually integrate the previously set aside dry ingredients into the wet mixture. Mix until combined, ensuring not to overwork the batter to maintain the bread's desired texture.

Transfer the final batter into the prepared loaf pan. Place in the preheated oven and allow to bake for approximately 55 to 60 minutes. A toothpick or knife inserted into the center of the bread should emerge clean, indicating its doneness.

Whilst the bread is cooling, commence the preparation of the glaze. In a small saucepan, combine the packed brown sugar and unsalted butter. Place over medium heat and bring the mixture to a boil. Continue heating until the sugar has dissolved entirely, which should take approximately 1 minute.

Remove the saucepan from the heat and integrate the heavy cream. Subsequently, sift in the confectioners’ sugar and kosher salt. Stir continuously until a smooth glaze is formed.

Allow the glaze to cool slightly for about 5 minutes. Once slightly thickened, pour it uniformly over the cooled banana bread.