Meg, I'm not sure how "authentic" you want to get with your carnitas...in our region of Mexico, they often cook the pork in lard. Yes, lard. And while I've never cooked it that way, I have eaten it, and it is delicious. But I know alot of Mexican cooks who cook carnitas like this: take 3-4 pounds of pork shoulder (loin would be too lean and get dry) and cut it into chunks - slightly bigger than you would for stew. Cover with water and add 3-4 cloves of garlic, a sliced onion, maybe a few serrano or jalapeno peppers. Bring to a boil and then simmer for 2-3 hours. If you want, you can then drain the broth (I always freeze it to make tamales) and pop the meat into a hot (450F) oven for about 20 minutes to carmelize a bit. (This step is optional - most Mexican homes do not have an oven).Serve with fresh hot corn tortillas, sliced radishes, avocados, good salsa verde, some cheese if you want. Just pop some of that tender yummy pork into the tortilla and fold it up like a taco. It is soooo good.