The day before cooking:
Make the wet rub by whisking all of the ingredients together. Set aside while you prepare the pork shoulder. The wet rub will thicken slightly as it sits.

Trim as much exterior fat from the pork shoulder as possible. Cut the shoulder into 3 pieces of roughly equal size. One side will likely have a bone, so it may be a little bigger than the other 2 pieces – which is no big deal. Add 1/3 of the wet rub to each piece and rub it in on all sides. Add the pieces of pork to a large dish, cover with plastic wrap, and refrigerate overnight.

Early on the day of serving:
The shoulder needs to cook for 11 to 12 hours so plan accordingly. Remove the pork from the refrigerator and let it sit at room temperature for 1 hour. Meanwhile, chop the onions and garlic. After the pork has rested for 1 hour, add about 3/4 of the chopped onions and about 3/4 of the chopped garlic to the bottom of the slow cooker. Add the pork then top with the remaining onions and garlic. If any liquids have come out of the pork while it was marinating, tilt the pan and spoon the liquid on top of the meat. Cook on low for 11 to 12 hours (or on high for 6 to 7 hours).

You will be shocked by the amount of liquid that comes out of the shoulder even though you did not add any extra water or broth to the slow cooker. When the pork is done, it will pull apart without any effort. Use a slotted spoon to remove the pork and onions/garlic from the juices in the slow cooker. Place the meat and onion mixture on a sided sheet pan and cover with aluminum foil and allow it to rest for 20 minutes. Discard the juices. The pork will taste great at this point and will be slightly sweet. You may serve the pulled pork after it has rested with (or without) a store-bought barbecue sauce.

I, however, like to go one extra step when making this pork. When the pork is almost done, start making the barbecue sauce by adding the roughly chopped onion and garlic to a food processor. Puree the onions and garlic and transfer the mixture to a medium sauce pan. Add the remaining sauce ingredients and stir to combine.

When the pork is resting after it has been removed from the slower cooker, preheat the oven to 350F. In addition, start heating the sauce ingredients over medium heat. Stir the sauce often as it heats so that it does not burn on the bottom of the sauce pan. It may splatter when it begins to simmer so feel free to use a splatter screen or a lid that is kept slightly ajar to allow excess moisture to escape. Simmer the sauce for about 15 minutes (about the length of time you are resting the pork). The sauce will darken considerably as it cooks.

Remove the foil from the pork. Use a couple of forks to shred the meat into smaller pieces. Add about 1/3 of the sauce to the pork and stir to combine. Then, spoon another third of the sauce on top of the meat but do not stir it in. Add the sheet pan to the oven and cook for about 1 hour or until the sauce is very thickened on top and beginning to char in a few places. After I add the pork to the oven, I continue to slowly cook the remaining third of the sauce over medium-low to medium heat until it has thickened (about 10 minutes longer or so). Transfer the extra sauce to a serving bowl.

When you take the pork out of the oven, stir it and serve immediately on hamburger buns. Pass around the extra sauce for those who prefer a wetter/sweeter barbecue sandwich.

Notes:
1) Don’t be tempted to buy a pork shoulder that is significantly bigger than 6 lbs. A 7 lb pork shoulder is a very tight fit in most slow cookers so 6 to 6 1/2 lbs is a better choice.
2) This tastes even better as leftovers. In fact, I rarely serve it on the day I make it. I prefer to make it a day or two in advance then just heat it up in the microwave. In this respect, it’s perfect party food.