Step 1: In a large bowl, whisk together the flour, granulated sugar, salt, baking powder, baking soda, and 1/2 teaspoon ground cinnamon.
Step 2: In a separate bowl, combine the mashed bananas, milk, melted butter, egg, and 1 teaspoon vanilla extract. Mix until well combined.
Step 3: Pour the wet ingredients into the dry ingredients. Stir until just combined, being careful not to overmix. A few lumps are okay.
Step 4: Lightly flour your work surface and turn the dough out onto it. Gently knead the dough a few times until it comes together.
Step 5: Using a rolling pin, roll the dough into a rectangle about 1/4 inch thick.
Step 6: In a small bowl, mix together the softened butter, brown sugar, and 1 tablespoon ground cinnamon until smooth.
Step 7: Spread the cinnamon filling evenly over the rolled-out dough. If using, sprinkle the chopped nuts over the filling.
Step 8: Starting from one long side, tightly roll the dough into a log shape. Pinch the edges to seal.
Step 9: Using a sharp knife or dental floss, slice the log into 12 equal pieces.
Step 10: Place the rolls in a greased 9x13 inch baking dish, spacing them slightly apart. Cover with a clean kitchen towel and let them rise in a warm place for about 30 minutes.
Step 11: Preheat your oven to 350°F (175°C).
Step 12: Bake the rolls for 25-30 minutes, or until golden brown and cooked through.
Step 13: While the rolls are baking, prepare the frosting. In a medium bowl, beat together the softened cream cheese and butter until smooth. Gradually add the powdered sugar and 1 teaspoon vanilla extract, mixing until well combined. Add 1-2 tablespoons milk as needed to reach your desired frosting consistency.
Step 14: Once the rolls are out of the oven and slightly cooled, spread the cream cheese frosting generously over the top. Serve warm and enjoy!