Did you know you can caramelize onions in the slow cooker? Apparently, you can. But, be forewarned, your entire place will smell like onions- not just the kitchen.
I found the recipe here. I added a touch of balsamic vinagrette dressing for fun. This is from a 1/2 full cooker after about an 8 hour cook time, with a pause after the first six, and then another pause after they were finished.