Step 1: Prepare the Dough

1. In a small bowl, dissolve the yeast in warm milk and let it sit for about 5 minutes until foamy.
2. In a large mixing bowl, combine flour, sugar, and salt.
3. Add the melted butter, mashed banana, egg, and yeast mixture. Mix until a soft dough forms.
4. Knead the dough on a floured surface for about 5-7 minutes until smooth and elastic.
5. Place the dough in a greased bowl, cover, and let it rise for about 1 hour or until doubled in size.

Step 2: Make the Filling

1. In a small bowl, mix brown sugar and cinnamon.
2. Spread the softened butter evenly over the rolled-out dough, then sprinkle the cinnamon-sugar mixture on top.

Step 3: Roll and Cut

1. Roll out the dough into a rectangle (about 12×18 inches).
2. Tightly roll the dough into a log and slice it into 12 rolls.
3. Place the rolls in a greased baking dish, cover, and let them rise for another 30 minutes.

Step 4: Bake

1. Preheat your oven to 350°F (175°C).
2. Bake the rolls for 20-25 minutes or until golden brown.

Step 5: Make the Glaze and Serve

1. Whisk together powdered sugar, milk, and vanilla extract until smooth.
2. Drizzle the glaze over the warm cinnamon rolls.
3. Serve and enjoy!