1. Heat up 1 cup of whole milk to 110°F and then pour it into the bowl of a stand mixer. Mix in 1 packet (2.5 tsp) of instant dry yeast first, followed by 1 egg, 2 egg yolks, 1/3 cup melted butter, 1 tsp salt, and 1/4 cup sugar.
2. Add in 4 cups of flour and mix until just combined (do not overmix). Let the dough rest for 5 minutes.
3. Using the dough hook, knead the dough for 5 minutes until it forms a smooth ball. If the dough is too sticky, add in more flour until a smooth ball forms.
4. Oil a large bowl and place the dough ball inside. Cover the bowl with a towel and let rise in a warm place for approximately 1 hour or until the dough has doubled in size.
5. In a separate bowl, mix together 1 cup packed brown sugar, 2 tbsp cinnamon, and 1/2 cup melted butter for the filling. Set aside.
6. Sprinkle flour onto a clean countertop and roll the dough into a 16"x24" rectangle with a rolling pin.
7. Spread the cinnamon filling over the entire rectangle and then roll up the 16" side so that you create a 24" long log.
8. Using floss, cut the log in half and then quarters; cut each quarter into three rolls to create 12 total rolls.
9. Butter a 9x13" baking dish and then place the rolls spaced evenly into the dish.
10. Cover the dish with a towel and let rise for approximately 40 minutes in a warm place until they have just about doubled in size.
(Note: Steps 11 and 12, likely involving baking and applying the frosting, are indicated as being in the comments of the original post and are not included here.)
