Heat milk and water in microwave for 45 seconds. Add to bowl of a stand mixer with honey and then sprinkle yeast on top. Let sit for 10 minutes until yeast activates (becomes foamy). If using instant yeast, this will only be a couple of minutes.
Meanwhile, mix flours, salt, and oats together in a large bowl and melt butter. You want the butter to be slightly cooled when adding to the dough.
Once yeast has activated, add butter to mixer bowl and with the dough hook attachment, beat on medium low. Slowly add flour and oats mixture and beat until a sticky dough ball forms.
In a lightly greased large bowl, add the dough ball. Cover with a linen towel and let rise until doubled (about an hour). If your house is cold and your oven has a "proof" setting, this works well too.
Pre-heat oven to 400 degrees.
Once the dough has doubled gently "punch down" (deflate) the dough and turn it onto a lightly floured countertop. Don't worry about kneading the dough, now it's time to just shape it. Flatten dough into a large rectangle and then fold the sides up into itself then roll the end closest to you away from you, rolling your dough up into a log.
Shape the dough by first flattening it into a large rectangle. Take the ends and fold them in towards the center of the rectangle, but not so much that they meet in the center. Turn down the top part of the dough onto the turned edges and then the bottom. Flip over and give a quick roll so you have a large log.
Grease a 9 x 5 loaf pan and add the dough with the folded edges down. Gently cover with a linen towel and do one final rise for 30 minutes.
Sprinkle the reserved oats on top of the loaf and then add to oven, middle rack. Bake for 35-40 minutes, but check at 30. You want the dough to be nicely browned, but be careful that it doesn't burn.
Remove from oven. Gently transfer to a cooling rack. You can check to see if it is done by giving the bottom of the loaf a thump with your thumb. If it sounds hollow, it's done. You could also use a thermometer and check for an internal temperature of 190° F.
Let the dough cool for at least 1 hour before slicing. Cutting it beforehand could make your center gummy. Enjoy!