In the bowl of a stand mixer, combine the warm milk, yeast, and a pinch of the granulated sugar. Stir gently and let it sit for 5-10 minutes, or until foamy. This indicates the yeast is active.

Add the remaining granulated sugar, melted butter, egg, mashed banana, and salt to the yeast mixture. Mix with the paddle attachment until well combined.

Gradually add 3 1/2 cups of the flour, one cup at a time, mixing on low speed until a shaggy dough forms. Switch to the dough hook attachment.

Knead the dough on medium-low speed for 8-10 minutes, adding the remaining 1/2 cup of flour as needed, until the dough is smooth, elastic, and pulls away from the sides of the bowl. It should be slightly sticky but not tacky.

Lightly grease a large clean bowl. Transfer the dough to the bowl, turning it once to coat. Cover the bowl with plastic wrap or a clean kitchen towel and let it rise in a warm place for 60-90 minutes, or until doubled in size.

While the dough is rising, lightly grease a 9x13 inch baking dish.

Once the dough has doubled, gently punch it down to release the air. Turn the dough out onto a lightly floured surface.

Roll the dough into a large rectangle, approximately 12x18 inches.

For the filling, brush the melted butter evenly over the entire surface of the dough, leaving a small border on one long edge. In a small bowl, combine the brown sugar, cinnamon, and nutmeg (if using). Sprinkle the mixture evenly over the buttered dough.

Starting from one of the long edges, tightly roll up the dough into a log. Pinch the seam closed to seal.

Using a sharp knife or unflavored dental floss, cut the log into 12 equal slices (about 1.5 inches thick). Place the sliced rolls cut-side down into the prepared baking dish.

Cover the baking dish loosely with plastic wrap or a kitchen towel and let the rolls rise in a warm place for another 30-45 minutes, or until puffy and almost doubled in size.

Preheat your oven to 375°F (190°C) during the last 15 minutes of the second rise.

Bake the cinnamon rolls for 25-30 minutes, or until golden brown and cooked through. If they start browning too quickly, you can loosely tent them with foil.

While the rolls are baking, prepare the cream cheese frosting. In a medium bowl, beat the softened cream cheese and softened butter with an electric mixer until smooth and creamy.

Gradually add the powdered sugar, one cup at a time, mixing on low speed until incorporated. Add the vanilla extract and 1 tablespoon of milk or cream, beating until smooth. If the frosting is too thick, add another tablespoon of milk/cream until it reaches your desired consistency.

Remove the baked cinnamon rolls from the oven and let them cool in the pan for about 5-10 minutes. Spread the cream cheese frosting generously over the warm rolls.

Serve immediately and enjoy!