Directions

1. Pour milk into a mug and microwave for 20 seconds until it is lukewarm, about 105-115 degrees F. Stir in yeast and allow to sit for 10-15 minutes until the top of the mixture looks foamy.
   
2. In a medium bowl, whisk together milk mixture, 2 tablespoons melted butter, sugar, egg yolk, and salt.
   
3. Add the flour a third at a time and using a spoon, mix well, until a thick, sticky dough forms and all the flour is incorporated. Dump the mixture onto a well-floured work surface and knead just until the dough is no longer sticky and forms a ball, about 10 minutes. Place dough into a greased bowl, cover with a damp towel, and allow to rise in a warm place for an hour, or until doubled in size.
   
4. In a small bowl mix together brown sugar and cinnamon. Once your dough has risen, turn out on a lightly floured surface. Use a rolling pin to roll the dough out to about 5 by 15 inches. Gently manipulate the corners and sides so you have a nice rectangle.
   
5. Spread 2 tablespoons softened butter over the entire dough and top with the brown sugar mixture. Roll up from the short side and pinch the seams shut. Use a serrated knife to cut the roll into quarters. Place in a 6 to 7-inch greased baking pan, cover tightly in plastic wrap, and let sit for 40 minutes until doubled in size. Place in the fridge overnight or up to 24 hours.
   
6. In a medium bowl, using an electric beater, beat together softened cream cheese, 3 tablespoons softened butter, powdered sugar, vanilla, and a pinch of salt, until well combined. Cover tightly and place in the refrigerator.
   
7. Heat the oven to 350 degrees. Take frosting out of the refrigerator to soften. Remove plastic wrap from rolls and place them into the preheated oven. Bake for 30 minutes until the tops are golden and center cooked through.
   
8. Spread frosting over rolls and serve warm.