The How to Cook Everything recipe for Carnitas is a variation on Bittman's Shredded Pork recipe. Both, I assume, are great taco fillers, which is what the carnitas I made were used for. Crispy little pieces of shredded pork: major drool factor. There are probably more authentic ways of doing this, and they may taste better, but these were damn good and they certainly did the trick.
In the mother recipe, you simmer chunks of pork shoulder along with a quartered onion, a bunch of smashed garlic cloves, bay leaves, cumin, a dried chile (I used ancho) and water to cover for about an hour or longer, until the meat is tender. Then you shred it, and you're done. The carnitas variation has you shred or chop the meat at this point, but then return it to the pot to cook further until all liquid is evaporated and the meat is getting nice and crispy.
Now, I simmered the pork in my enormous 8 qt. dutch oven and it took over 12 cups of water to cover the pork. I was not about to simmer this stuff for 12 hours waiting for all that water to cook off. So I shredded the meat, removed most of the liquid (strained it and froze it as pork stock, natch), returned the meat to the pan, added a bit of neutral oil and simmered until the meat was getting crispy. Then I let it cook a while longer, because in my book the crispier the pork is, the better.
It worked, and it was great. There are more authentic ways of making carnitas, I'm sure, but let me tell you: these tacos were pretty effing good, especially with the leftover Red Beans with Meat I'd stashed in the freezer. The remaining toppings were roasted tomato salsa (Trader Joe's) and ricotta salata--could've used something green like lettuce or my favorite, the gringotastic cucumber, but these were pretty delicious as it was. The leftovers I just ate mixed with a big bowl of rice and beans (cheese on top) for lunch.