1. Warm milk to 105-115°F, add yeast and a pinch of sugar, and let rest for 10-15 minutes until foamy.
2. In a medium bowl, mix the milk-yeast mixture with melted butter, granulated sugar, egg yolk, and salt.
3. Gradually add flour and mix until a soft dough forms. Knead on a floured surface until smooth.
4. Place dough in a greased bowl, cover, and let rise for 1 to 1.5 hours until doubled.
5. Mix brown sugar and cinnamon for the filling.
6. Roll dough to a 5 x 15-inch rectangle. Spread butter and sprinkle with cinnamon sugar.
7. Roll dough tightly into a log, cut into 4 rolls.
8. For same-day baking, place rolls in a greased 6-7 inch dish, rise for 45-60 minutes. Preheat to 375°F.
9. For overnight prep, refrigerate rolls up to 24 hours, then rise 1-2 hours before baking.
10. Bake rolls for 15-22 minutes until golden brown, cool for 5-10 minutes.
11. Beat cream cheese and butter until smooth. Add powdered sugar, vanilla, and salt; spread on warm rolls.