Cut various slits into the pork and stuff the garlic slices into them. I like to make long slices along every side, making this part easier.
Rub down the pork shoulder with the prepared marinade. Cover and refrigerate at least 1 hour. Overnight is better for more flavor penetration.
Heat oven to 300 degrees F.
Transfer the pork shoulder to the bottom of a roasting pan or large baking dish, skin side up. Wipe the skin clean of any marinade and excess moisture. This will help with the crispy skin.
Pour 1 cup water and 1 cup sour orange juice into the bottom of the roasting pan, then cover the pan with foil, leaving no gaps.
Bake the pork shoulder for 3 hours.
Raise the oven temperature to 400 degrees F. Rotate the roasting pan around for even cooking and remove the foil. Pat the skin dry with a paper towel. Add 1-2 cups additional water/sour orange if the bottom is too dry.
Bake for 1-2 hours or longer, until the internal temperature of the pork reaches 210 degrees F when measured with a meat thermometer, or when a a skewer can pierce the meat easily.
If cooking with skin-on, the skin should be nice and crispy, but if it is not, turn up the oven temperature to 500 degrees F and bake an additional 10 minutes, or until the skin is browned and crispy.
Remove from heat and rest 20 minutes. Carve and serve.
For Serving. Drain the drippings from the roasting pan into a bowl and skim the fat. Stir in vinegar and chopped cilantro. Add salt to taste. Serve with the finished pork as a dipping sauce or gravy.