Place oatmeal in a large mixing bowl or the bowl of a stand mixer along with maple syrup, cinnamon, oil and salt. Stir in hot milk and mix with a wooden spoon or spatula. Set aside for 10 minutes.
Stir in the instant yeast followed by 2 cups of bread flour and 1 cup of whole wheat flour.
Mix with the wooden spoon until a shaggy dough forms. Then begin kneading it by hand or in a stand mixer with the dough hook attachment. Knead at low speed, adding a tablespoon of whole wheat flour at a time if the dough is too wet. On a humid day I needed to add just ¼ cup more of flour.
Continue kneading the dough for seven more minutes in a stand mixer at medium speed, or by hand for 10 minutes. The dough should be soft and smooth with a slightly tacky look to it, but it shouldn't stick to your hands when you touch it. You don't want a stiff dough because that will result in a dry bread.
Form the kneaded dough into a smooth ball. Coat the bowl with oil and place the ball of dough in it. Coat the top with oil. Cover with a tight lid or cling wrap and set in a warm spot for an hour.
After an hour the dough should have more than doubled. Turn it out onto an unfloured surface and pat it down lightly with your hands to deflate.
Still using your hands, shape the dough into a rectangle. Flip the dough over so the smooth side is on the bottom, then fold the edges of the dough over along the long side. Begin rolling the dough. With the seam side down, tuck the ends over and under to form a loaf. (See process shots above for guidance on shaping the loaf).
Place the loaf in a lightly oiled loaf pan. Cover loosely with oiled cling wrap. In an hour the loaf should be springing well above the rim of the pan.
About 15 minutes before the bread has risen preheat the oven to 350 degrees. Brush the loaf, if desired, with some milk and sprinkle on some oats. Bake the bread for 40 minutes. Cool on a wire rack for 30 minutes, then remove carefully from loaf pan and continue cooling on rack.