In the bowl of a stand mixer, stir warm water together with yeast an 3 tablespoon sugar until mostly dissolved. After 10 minutes, mixture should be foamy. (If nothing has happened, throw it out and try again OR buy fresher yeast.)
Add in remaining 3 tablespoons of sugar and 2 cups of flour and start to mix with the machine on low to medium speed with the dough hook attachment. Stir in melted butter and salt. Add in another 1-2 cups and let the machine work to knead it into the dough, about 2 minutes or kneading on low to medium speed. Add in remaining 2 cups of flour (if needed) bit by bit, letting the machine knead in the flour for several seconds before adding in more flour. Only add in enough flour to get a dough that is mostly smooth, has cleaned the sides of the bowl, the bottom is still sticking and when you touch it with your hands, it is tacky but not sticky enough to stick to your hands. This whole process should take about 10 minutes.
Scrape the dough out of the bowl and into a well greased large bowl. Roll it around to coat in oil, over and rise on the counter 2-3 hours. Alternately, you can refrigerate 2-3 hours to overnight.
Filling and Cutting Orange Rolls-
In a medium-size bowl, stir sugar, orange zest and cinnamon together until combined. Set aside.
Flour a clean surface and dump risen dough onto the board. Sprinkle the dough and rolling pin in more flour and start to roll a 24"x18 rectangle (approximately). As you roll, be sure to move the dough around to ensure no sticking. Add more flour as needed.
Using your fingers, spread the soft butter over the entire piece of dough, leaving a 1 inch border along the top of a longer 24" side. Sprinkle the orange sugar mixture over the butter evenly.
Roll dough neatly into a tight swirl, towards the border of dough without sugar. Bring entire log of dough towards you, moving the seam side down to hold in place. Using a serrated bread knife, cut into 1 1/2" rolls (approximate is fine) and place onto buttered parchment paper on a lightly colored half sheet pan. (You should end up with 16 nice cinnamon rolls and 2 small end pieces that you can squeeze onto the sheet pan too or just toss.)
Cover rolls with plastic wrap and rise 1 hour or until puffed and pretty. Bake at 350 degrees for 20-25 minutes or until tops are golden brown.
For the Orange Cream Cheese Frosting
In a small bowl, measure out all ingredients for frosting. Mix slowly until incorporated and then increase the speed to whip until completely smooth and light.
Spread frosting overtop warm orange rolls. Serve warm or at room temperature.
Don't let the 6 cup increment of flour fool you! This is an approximation. Only add enough flour to get you a dough that:
has cleaned the sides of the mixing bowl
still sticks to the bottom of the mixing bowl
is mostly smooth
is tacky when touched but isn't sticky enough to leave a residue or stick
When in doubt, leave the dough a little on the sticky side and then refrigerate. You can always add in more flour later as you're rolling out the rolls to compensate.