Preheat your oven to 350°F (175°C). Grease a 9x5-inch loaf pan or line it with parchment paper.
In a large mixing bowl, combine the mashed bananas, granulated sugar, brown sugar, melted butter, egg, and vanilla extract. Mix until well combined.
Add the baking soda and salt to the banana mixture, then gradually stir in the flour until just combined. Be careful not to overmix. If using, fold in the chopped walnuts.
In a small bowl, mix together the brown sugar and cinnamon for the filling.
On a lightly floured surface, roll out the banana bread dough into a rectangle about 1/2 inch thick. Spread the softened butter over the dough, then sprinkle the cinnamon filling evenly on top.
Starting from one long side, carefully roll the dough into a log. Slice the log into 1-inch thick rolls and place them in the prepared loaf pan.
Bake for 25-30 minutes, or until the rolls are golden brown and a toothpick inserted in the center comes out clean.
While the rolls are baking, prepare the glaze by whisking together the powdered sugar, milk, and vanilla extract in a small bowl until smooth.
Once the rolls are done baking, allow them to cool in the pan for about 10 minutes before transferring them to a wire rack. Drizzle the glaze over the warm rolls before serving.