Carnitas are usually made of pork that has been cut into chunks and slow-cooked in fat, then crisped up before serving. Since I usually have to spend eight hours a day at a place called "work" and I don't have three hours AFTER work to wait for dinner, I decided I wanted to try doing a slow-cooker version of carnitas instead.
Part of what makes carnitas so good is the crispy rendered bits of meat. When you're cooking a pork butt in a crockpot, you don't get those bits. I came up with two ways to deal with this, each of which was only moderately successful on its own, but done in conjunction seemed to really make a difference. The first thing I did was brown the entire roast, one side at a time, in a very hot pan. This ensured that I'd at the very least not end up with flabby chunks of fat in the crock-pot at the end of 10 hours of cooking. It also, I think anyway, made the flavor of the meat deeper than just plopping it in the slow-cooker would have. The second thing I did was, after shredding the cooked meat, I spread it out in a wide, shallow pan and chucked it into a 450 degree oven for 10 minutes. The top surface of the meat got nicely crisp and did a good job of emulating the crispy bits of traditional carnitas.
I'm fairly happy with how these came out, but I'll definitely try them again with the addition of some citrus juice and spices to the cooking liquid. This time around, I just used a little chicken stock, a bunch of minced garlic, salt, pepper and oregano. I did mix some onion powder and and cumin into the meat as I was shredding it as well, but next time I'll definitely add these at the beginning of cooking so to better infuse the meat with flavor.