In a large pot, combine the stock, tomato paste, garlic, onion, bay leaf, cumin, oregano, salt and pepper. Stir everything to combine. Add pork and water to cover. Bring to a good simmer. Turn heat to low and cover. Braise for 3 to 5 hours until meat can be easily pulled apart. You want it to fall off the bone.

(The original recipe says to braise for 3 hours on low heat, but after checking it, the water was not on a low simmer, so I had to turn up the heat a little and braise it for 5 hours.)

When meat is ready, transfer to a cutting board and pull it into 3- to 4-inch pieces. You can trim some of the fat off at this point, but you’ll want to leave some on.

Transfer to a baking dish and bake for 25 to 30 minutes in a 450-degree oven. The fat will help caramelize the meat. You want it to look crispy around the edges.

Carnitas means small meats so you will want to chop the meat into little pieces.

Now you can begin assembling the tacos. Smear some guacasalsa (or guacamole) on the tortilla. Add meat, some chopped onion, cilantro, queso fresco or cotija and squeeze on some lime.
Absolutely delicious! I served this with Spanish rice and refried beans.

(By all means, use regular store-bought tortillas if you wish. However, Bajio sells them per dozen and they are delicious! $3.99/dozen and they can even cook them for you!)