Divide dough into 2 parts and grease two loaf pans.
Melt butter in a shallow dish. Mix cinnamon and sugar in another shallow dish.
Make four slices in each loaf, without going completely through the loaf. Roll the dough in the butter to coat.
Roll buttered dough in the sugar mixture, making sure to coat the sliced areas well.
Arrange dough in loaf pans, then cover and let rise 30 minutes.
Preheat oven to 300 degrees.
Bake loaves for 35 minutes, or until golden brown and hollow sounding when tapped.
Remove from oven and cool a few minutes in pan before turning out onto a wire rack. If glaze is desired, glaze while on the rack and still warm.