Turn your dough out onto a lightly floured countertop and roll into a large rectangle about ⅛" thick. Use a bench scraper to square off the dough as you roll to keep a rectangular shape. It doesn't have to be perfect. Dust the counter lightly with flour as needed to keep the dough from sticking.
Arrange the dough rectangle so one of the long edges is facing you. Brush off any excess flour, then spread about ⅔ of the cinnamon sugar filling onto the surface of the dough. Leave about an inch along the top edge clear of filling.
Roll the dough into a log starting with one of the bottom corners closest to you. For a tighter roll with more layers, gently lift and stretch the dough slightly toward your body before each forward roll.
Gently flatten the log against the counter using your hands or a rolling pin. Be gentle but firm — you don't want to tear the layers of dough and filling inside it. You just want to flatten it into a wide strip.
Flip the dough over so the seam side is facing up. Spread the remaining cinnamon sugar filling along the top of the dough.
Starting from one end of the dough, roll the the strip up into a coil and tuck the open end underneath it. Place inside a well-greased 5" oven-safe baking dish. Cover and set aside to rise for 1 hour in a warm spot (or 8-12 hours in the fridge) until just slightly puffy.
During the last 30 minutes of rising time, preheat the oven to 350°F.
Bake 35-40 minutes, until the internal temp at the center registers 190°F on an instant read thermometer. The top will be deeply browned and feel hard to the touch. If the top seems to be browning too quickly, after 15 minutes, tent the cinnamon roll with aluminum foil.
Remove from oven. Let cool for 10-15 minutes, then spread generously with frosting.