We can order these from our CSA, and I love them... but they need to be cooked forever, so the crockpot is really only the way to go. We've tried soaking them overnight, but they didn't have the nice chewy consistency they get in the slow cooker.
2 c whole oats, or "groats," or whatever you want to call them
5 c milk, water, or any combination
1 shredded apple, skin on
Handful of raisins or dried cranberries
Sprinkle of cinnamon or apple pie spice
Pinch of salt
Mix everything in the crockpot & turn on low. After a few hours, check it to make sure it isn't sticking and add more liquid if necessary.
It's usually done after 5-6 hours, although cooking it longer doesn't hurt. I still haven't been able to cook this overnight without the edges burning, because you really do need the stirring step, but I've also just tossed the edges & the rest of it is fine.