Set out 5 eggs on the counter for at least an hour to get to room temperature.
Whip or use a stand mixer with whisk attachment to combine all the eggs (yolks and the one whole egg) sugar, melted butter, and buttermilk. Add in about 2 cups of the flour and the yeast and salt. Mix on low so you don't splatter the flour, then increase speed if you're using a mixer. Otherwise little caution is necessary. When you have a pancake batter like consistency switch to the dough hook attachment for your mixer and add in all but 3/4 cup of the flour. Start it on low speed and give it about 2 minutes to knead with the hook. If you're working this by hand, use a spritz of cooking spray on your hands to help keep the dough from sticking to them. After 2 minutes, if the dough still looks and feels wet go ahead and add more flour at about 1/3 cup at a time. After about 3 more minutes you should find that the dough is balling together more easily. Take out the dough ball and knead by hand for about 30 seconds, and shape it into a ball. Oil a large smooth bowl and set the dough ball
Punch the dough down to get the excess air out. Lightly flour your hands and a work surface. Work the dough into a rectangle about one and a quarter times the size of your baking dish using your hands and a rolling pin.
Using a basting brush, baste one side of the flattened dough with an even layer of melted butter. In a medium bowl, combine cinnamon, brown sugar and salt. Sprinkle the brown sugar mixture on the buttered dough til you have an even layer, then lightly press the sugar into the dough so it sticks well.
Start rolling the cinnamon roll sheet by taking one of the long sides of the dough rectangle and rolling inward. Keep rolling inward, trying to keep the same level of tension throughout to keep the roll even. When you get to the end, crimp the end against the side of the roll by pinching and giving the seam a little twist. Roll the cinnamon log over so the seam is down, then take a sharp knife and cut the log in half. Set the two halves parallel and touching, then cut them both at the same time into thirds, then half each third. You should end up with 12 cinnamon rolls.
Butter a 9 x 13 baking dish and set the rolls into the buttered baking dish and cover with saran wrap. Let rest in your fridge overnight or up to 16 hours before serving.
When you're ready to bake, first proof your dough by filling a (separate) baking dish half full of boiling water and setting that dish in the oven. Then put the dish of cinnamon rolls into the oven beside the hot water pan and close the door. Give them 30 minutes for the yeast to wake up and start the buns rising.
Remove the baking dishes from the oven and preheat to 350*. When the oven has preheated, cook the rolls for about 30 minutes.
Remove from oven and let cool on a cooling rack.
For a cream cheese frosting, whisk cream cheese, milk, and powdered sugar. When the cinnamon rolls have cooled slightly, baste with the frosting.
