For the Dough:
In a large bowl, combine the warm milk, granulated sugar, and yeast. Let stand for 5-10 minutes until foamy.
Stir in the melted butter, eggs, and salt.
Gradually add 3 1/2 cups of flour, mixing until a soft dough forms. If the dough is too sticky, add more flour, a tablespoon at a time, until it pulls away from the sides of the bowl.
Turn the dough out onto a lightly floured surface and knead for 5-8 minutes until smooth and elastic.
Place the dough in a greased bowl, cover with plastic wrap, and let rise in a warm place for 1 to 1.5 hours, or until doubled in size.
For the Filling:
In a small bowl, combine the softened butter, brown sugar, and cinnamon. Mix until well combined and spreadable.
Once the dough has risen, punch it down and turn it out onto a lightly floured surface.
Roll the dough into a 12×18 inch rectangle.
Spread the cinnamon-sugar filling evenly over the dough, leaving a small border along one long edge.
Roll up the dough tightly, starting from the long edge with the filling.
Cut the roll into 12 equal slices.
Place the slices into a greased 9×13 inch baking dish, cut side up.
Cover the dish and let the rolls rise for another 30-45 minutes, or until puffed.
Preheat your oven to 375°F (190°C).
Bake for 20-25 minutes, or until golden brown.
For the Frosting:
While the rolls are baking or cooling, beat the softened cream cheese and butter together until smooth.
Gradually beat in the powdered sugar until combined.
Stir in the vanilla extract and 2 tablespoons of milk. Add more milk, one tablespoon at a time, until the frosting reaches your desired consistency.
Once the cinnamon rolls are slightly cooled, spread the frosting generously over the top.