Activate yeast in warm milk: pour warm milk into a bowl, then add sugar, mashed banana, melted butter, and egg. Stir until smooth and foamy around the edges.

Knead in flour mixture: add flour, cinnamon, and salt, then knead until the dough is smooth and elastic, about 8 minutes. The dough should look slightly tacky but hold together as you knead.

Rise the dough: place dough in a lightly greased bowl, cover, and let rise for 1 hour. It should double in size and look puffed and airy.

Roll and fill: roll dough into a 12x18 rectangle, then spread softened butter filling over the surface. Sprinkle brown sugar, cinnamon, and nutmeg evenly, then lay banana slices across the top.

Roll tightly and cut: roll the dough tightly into a log and cut into 12 rolls. Arrange cut sides up on a sheet pan so the layers stay visible.

Second rise: cover rolls and let rise for 30 minutes. They should look larger and feel soft when gently pressed.

Bake: bake at 375°F for 22–25 minutes, until the tops are golden and the centers look set. You should see slightly browned edges and a springy texture.

Cool briefly: cool the rolls for 10 minutes after baking. This helps the frosting melt into streaks instead of disappearing.

Drizzle frosting: mix cream cheese, butter, powdered sugar, and vanilla until smooth, then drizzle over warm rolls. Finish with any visible banana slices that may peek through the swirls.