Dough

1. In a medium bowl, whisk the flour, yeast, and salt. Set aside.
2. In the bowl of a stand mixer, whisk the melted butter, sugar, sour cream, and egg. Attach the bowl to the mixer, and using the dough hook on low speed, add the flour mixture and milk and mix to combine. Increase the mixer to medium-low speed and mix for 5-7 minutes or until the dough is smooth and elastic. It's ok if it is still slightly sticky. 
3. Scrape the dough from the sides of the bowl and drizzle with a mild oil. Turn the dough so that it is lightly greased on all sides. Loosely cover the bowl and allow the dough to rise in a warm place (75°F/24°C) until doubled in size, about 1 hour.
4. Lightly grease a 13x9-inch baking pan with butter.
5. Turn the dough onto a lightly floured surface and lightly punch down to release some of the air. Roll dough into a 12x18-inch rectangle.

Filling

1. In a small bowl, mix the brown sugar and cinnamon.
2. Spread the softened butter onto the dough, leaving a 1/2-inch border along one of the long edges. Sprinkle the sugar mixture over the butter.
3. Begin with the long edge that has the sugar mixture and roll the dough tightly into a log.  Pinch the seam to seal, trim ends, and slice into 12 rolls. Arrange the rolls in the prepared pan and allow them to rise in a warm place until they are puffed, about 30 minutes.
4. Preheat oven to 350°F/177°C.
5. Bake the cinnamon rolls for 30-35 minutes or until the tops are lightly golden brown. Allow the rolls to cool for 15 minutes before frosting.

Cream Cheese Frosting

1. With a mixer, beat the cream cheese and butter on medium-high speed for 3-4 minutes until light and fluffy. Add the vanilla and beat until combined.
2. With the mixer on low speed, mix in the powdered sugar until combined. Increase the mixer to medium-high speed and beat the frosting until fluffy. Spread onto the warm rolls.