In a large mixing bowl, combine the water, oats, maple sugar, honey, butter, salt and cinnamon. Let cool to lukewarm.
Add the yeast and flours, stirring to form a rough dough. Knead (about 10 minutes by hand, 5 to 7 minutes by machine) until the dough is smooth and satiny. Transfer the dough to a lightly greased bowl, cover the bowl with lightly greased plastic wrap, and allow the dough to rise for 1 hour.
Divide the dough in half, and shape each half into a loaf. Place the loaves in two greased 8 1/2 x 4 1/2-inch bread pans. Cover the pans with lightly greased plastic wrap and allow the loaves to rise till they've crowned about 1 inch over the rim of the pan, about 1 hour.
Bake the loaves in a preheated 360°F oven for 33 minutes.* Remove them from the oven when they're golden brown, and the interior registers 190°F on an instant-read thermometer. Yield: 2 sandwich loaves.
*If your oven can't be set at 360°F, set it at 350°F and bake the bread for 35 to 40 minutes.