Making The Filling
Combine the dark brown sugar and the ground cinnamon with a pinch of salt.
Roll the dough out into a wide rectangle as thin as possible, using a lightly floured surface.
Spread the butter over the dough, leaving a thin border all the way round.
Scatter the cinnamon sugar mixture over the butter.
Roll the dough into a long cylinder, as tightly as possible and cut it into even swirl slices about 2cm thick.
Grab a couple of deep baking dishes and brush them with oil.
Place the rolls around the outside of the dish with very little space between them and one in the middle.