Activate the Yeast:

In a large bowl, pour warm milk and sprinkle yeast and granulated sugar on top. Let sit for 5 minutes until foamy.

Make the Dough:

Add melted butter, eggs, salt, and mashed bananas to the yeast mixture and stir to combine. Gradually add flour, one cup at a time, until dough forms and pulls away from the sides of the bowl. Dough will be slightly sticky.

Knead the Dough:

Turn dough onto a lightly floured surface and knead for 10 minutes until smooth and elastic. Add flour as needed to prevent sticking, but avoid over-flouring.

First Rise:

Place the dough in a greased bowl, turning to coat. Cover with a towel or plastic wrap and let rise in a warm area for 1 hour, or until doubled in size.

Make the Filling:

In a bowl, mix softened butter, brown sugar, and cinnamon until smooth and spreadable.

Roll and Fill:

Punch down dough and roll into a 20x14-inch rectangle on a floured surface. Spread filling evenly, leaving a small border along one long edge. Sprinkle with chopped walnuts if using.

Shape the Rolls:

Starting from the long edge without filling, tightly roll into a log. Pinch the seam to seal. Slice into 12 equal rolls, about 1.5 inches thick.

Second Rise:

Place rolls in a greased 9x13-inch baking dish. Cover and let rise for 30 minutes until puffy. Preheat oven to 350°F during this time.

Bake:

Bake for 25–30 minutes, until golden brown and internal temperature reaches 190°F.

Frost:

While rolls are warm, beat cream cheese, butter, powdered sugar, and vanilla until smooth. Spread over warm rolls and serve.