In a large bowl, combine flour, oat bran, brown sugar, dry yeast, salt and cinnamon. Heat water and butter until very warm (102° to 130°F); gradually stir water into dry ingredients. Knead on lightly floured surface until smooth and elastic, about 6-8 minutes. Cover; let rest 10 minutes
Roll dough on lightly floured surface to 12”x 7” rectangle. Beginning at short end, roll up tightly as for jellyroll. Pinch seam and ends to seal. Place, seam side down, in a greased 8-½” x 4-½” loaf pan. Cover, let rise in warm, draft-free place until doubled in size (about 50-60 minutes).
Bake at 375°F for 30-35 minutes or until done. Remove from pan; cool on wire rack. Allow to cool before slicing.