First prepare the pan. Melt 5 tablespoons of butter for the filling and use some of that to butter your loaf pan. Line the bottom and longer sides with parchment paper, leaving some overhang, for easier lift-off when the bread is baked. Brush the parchment with butter too. Set aside.
Take your dough out of the refrigerator, lightly flour your work surface and roll out the dough into a rectangle, about twice the length of your loaf pan and about 1/4 inch (6 mm) thick.
Brush the dough with melted butter, leaving a 1 inch (2.5 cm) border at the top longer side of your rectangle.
Mix brown sugar with cinnamon, then sprinkle it all over the dough and pat it down. Tightly roll the dough into a log, making sure that the seam is on the bottom. If it’s sticking to your counter, lift and roll it with a dough scraper.
Slice the log in two crosswise, so that you get two smaller logs. Put the logs into your prepared pan - place them side by side or one over the other to form an X shape. Both bake the same, the latter just gives you more cinnamon layers in the middle.
Pat down the logs slightly, so the dough fills up the pan on all sides. Let it rise at room temperature until doubled (this will take up to an hour, depending on how cold the dough and kitchen are).