Mix together the seasonings in a small bowl.
Start by cutting the pork butt into small chunks (like 2 in thick).
Pat the meat dry and then rub about 3/4 of the seasoning over all sides of the meat.
Heat the oil/butter in a skillet or pan on high heat.
Once it is hot, add the meat just long enough to sear each side (until it's golden brown).
Once you've seared each side of all pieces of the meat (you may need to do this in batches depending on the size of your pan), place the meat in the crock pot.
Slice 1/2 on the onion into rounds and place that over the meat.
Using a vegetable peeler, peel the skin of the orange and add those peels to the meat as well.
Sprinker the remaining seasoning on top.
Lastly, squeeze in the juice of the entire orange over the top.
Cook on high for 4-5 hours.
While the meat is in the crockpot, finely dice the rest of the white onion and mix it with the chopped cilantro. Add a little salt and store in the refrigerator until you need it.
Once it's done cooking, remove and using two forks, separate the meat from the fat and then shred the meat. (I know this is a pain, but the fat is what gives the meat good flavor.)
Place the meat on a pan lined with parchment paper.
Juice one lime over the top and then season with a little bit of salt as well.
Turn your oven to "broil/high" and put the meat in for about 4-5 minutes or until slightly crispy.
Serve in tortillas (microwave in wet paper towel to soften), and top with the onion/cilantro mixture and avocado!
