In a medium glass bowl add the warm water, 1 tbsp of sugar, and active dry yeast. Stir well and set aside to rise for 15 minutes.NOTE: Do not add the water, sugar, and yeast to a metal or aluminum bowl. The active dry yeast won’t activate in the bowl of a stand mixer. It’s better to let it rise in a glass bowl and then transfer it to your stand mixer bowl.
While yeast is rising add room temperature buttermilk, ½ cup sugar, melted butter, salt, and eggs to the bowl of a stand mixer. Use whisk attachment o on low to whisk together.
Once the active dry yeast has activated and is foamy on the top pour it into the bowl of the stand mixer. Using the whisk attachment, whisk the mixture together for 20 seconds.
Remove the whisk attachment and add the dough hook. Add 5.5 cups of all purpose flour to the bowl and mix on low for 40-60 seconds. Turn up the speed to medium and allow dough to mix together for 8-10minutes. (Dough will be sticky.)
Remove the bowl from the stand mixer and cover with foil for 10 minutes.
In a separate medium bowl combine ¼ cup softened butter, light brown sugar, sugar, and cinnamon. Use a fork to mash butter into the mixture. It should have a crumbly consistency once mixed. Set aside.
While the dough is still rising, lightly flour a large flat area on your kitchen counter. Remove dough from the bowl and roll dough out flat into a 12 x 16 rectangle. Using a sharp knife, cut the excess dough if not in a perfect rectangle shape.
Use a rubber spatula to spread out ¼ cup softened butter on the surface of the dough, all the way to the edges. Sprinkle the cinnamon filling evenly over the surface of the dough. Using a rolling pin lightly press the cinnamon mixture into the dough.
Roll the dough up tightly into a long log. It should measure roughly 16 inches. Using a sharp knife, cut the two uneven ends of the dough off and discard. Cut into 16 large rolls and place into a greased 9x13 flat baking dish. (***)Alternatively, you cancut a piece of sewing string, place it under the dough and bring each end up and around and crisscross and pull the opposite directions and it slices it and doesn't smash it down like a knife might.
Place in a preheated oven and bake at 375 degrees for 20-22 minutes.
While the cinnamon rolls are baking, combine frosting ingredients in a medium mixing bowl. Using a hand mixer, mix together until no lumps remain.
When the cinnamon rolls are done baking, remove from the oven and let sit for 3 minutes and then frost with the cream cheese frosting.