01 - In a large mixing bowl, dissolve yeast in warm milk and let stand 5 minutes until foamy. Add melted butter, mashed bananas, granulated sugar, egg, and salt; mix to combine. Gradually add flour, mixing until a shaggy dough forms. Knead for 8 to 10 minutes by hand or with a stand mixer fitted with a dough hook until smooth and elastic.
02 - Transfer dough to a lightly greased bowl, cover, and let rise in a warm place for about 1 hour, or until doubled in size.
03 - In a small bowl, thoroughly mix brown sugar, ground cinnamon, and nutmeg.
04 - Punch down risen dough. On a floured work surface, roll dough into a 16 by 12-inch rectangle. Evenly spread softened butter over the surface and sprinkle with the prepared cinnamon sugar filling.
05 - Starting from the long edge, tightly roll up the dough into a log. Slice evenly into 12 individual rolls.
06 - Arrange rolls cut side up in a greased 9x13-inch baking dish. Cover and let rise for 30 to 45 minutes until puffy.
07 - Preheat oven to 350°F. Bake rolls for 22 to 25 minutes, or until golden brown.
08 - While rolls bake, beat together softened cream cheese, butter, powdered sugar, milk, and vanilla extract until smooth.
09 - Let baked rolls cool for 10 minutes. Generously spread icing over warm rolls and serve immediately.