1) Combine all of the ingredients, and mix until cohesive. Cover the bowl, and let the dough rest for 20 minutes, to give the oats a chance to absorb some of the liquid. Then knead — by hand, stand mixer, or bread machine — to make a smooth, soft, elastic dough.
2) Place the dough in a lightly greased bowl, or in an 8-cup measure (so you can track its progress as it rises), and let it rise for 1 to 1 1/2 hours, until it's risen noticeably. It won't necessarily double in bulk.
3) Gently deflate the dough, and shape it into a 9" log. Place the log in a lightly greased 9" pain de mie (pullman) pan, pressing it gently to flatten.
4) Place the lid on the pan (or cover with plastic wrap, for a better view), and let the dough rise until it's about 1" from the top of the lid, 60 to 90 minutes. Towards the end of the rising time, preheat the oven to 350°F.
5) Remove the plastic (if you've used it), slide the pan's lid completely closed, and bake the bread for 30 minutes.
6) Remove the lid, and bake for an additional 5 minutes, or until an instant-read thermometer inserted into the center registers at least 190°F.
7) Remove the bread from the oven, and turn it out of the pan onto a rack. Run a stick of butter over the top, if desired; this will yield a soft, buttery crust. Cool completely before cutting; wrap airtight and store for several days at room temperature.
Yield: 1 standard loaf.