Keep your butter frozen until you use it throughout the process.
In a large bowl, stir together the flour, salt, cinnamon, and sugar. Using a spatula or wooden spoon, stir in the 1/4 cup separated frozen grated butter until evenly distributed.
Slowly add in the cold water, stirring, until a dough begins to form, and the flour is completely incorporated. Turn the dough out onto a floured surface and knead once or twice to finish incorporating all the ingredients. The dough should be fairly soft and easy to work with.
Working quickly, roll the dough into a large rectangle, about 8 inches by 15 inches. Note that the size does not need to be perfect here. Sprinkle half of the remaining frozen butter onto two thirds of the rolled out dough.
Fold the dough into thirds, starting by folding in the side without any butter on it. Gently pinch the edges to lightly seal the dough.
Roll out the dough again, re-flouring your surface if needed, to the same size, and repeat the butter and folding process with the second half of the frozen butter.
Once again, roll out the dough into a large rectangle, and fold into thirds, without any more butter (you should have used it all). Repeat the process two more times, so a total of 5 times.
Immediately wrap the dough in plastic wrap, and pop it in the fridge for at least 30 minutes before using.
In a medium bowl, stir together the brown sugar, 1 cup sugar, cinnamon, and salt. Set aside the remaining sugar in a bowl to use later.
Lightly grease a 12 cup muffin tin. Set aside.
Remove the dough from the fridge, and roll it out on a floured surface to a large rectangle, about 10 by 16 inches.
Evenly sprinkle the filling mixture over the rectangle, and press down into the dough with your hands, or with your rolling pin.
Starting on the longer side of your rectangle, roll the dough into a tight spiral log. Wrap the dough tightly in plastic wrap, and freeze for 30 minutes.
Remove the dough from the freezer, and trim off the edges of the log. Then, cut the log into 12 equal slices by cutting the log in half, each of those halves in half, and then each remaining piece into thirds. Place each slice into your prepared muffin tin, and place the tray in the fridge for 20 minutes.
While your rolls are chilling, preheat your oven to 400 degrees. Take the rolls out of the fridge and place directly into the preheated oven. Bake for 20-25 minutes, or until golden brown on top through to the center.
Right after you remove the rolls from the oven, run a knife along the edges of each roll to loosen, and remove from the pan while hot- they will stick to the pan if you do not remove them quickly enough.
Cool the rolls for about 5 minutes, and then dip the tops into the remaining sugar that we set aside earlier. Enjoy warm!