Preparation Mash the garlic, oregano, salt, and pepper into a paste in a blender; place the mixture in a bowl and stir in the oil and vinegar. Take a knife and separate the skin (do not stab the skin) from the pork about 90%. Rub the garlic paste mixture between the skin and pork, being sure to make ½ inch incisions and 1 inch deep so the paste can penetrate the meat and pull out the moisture - this will help form a crust on the outside when cooked. Cover the pork with plastic wrap and marinate in the refrigerator for at least 3 to 6 hours. Allow the meat to sit at room temperature for 30 minutes before cooking. Preheat the oven to 350 and cook roast for 2 hours at 350 and 3 and 1/2 hours at 325 degrees F. Roast the pork for 35 minutes per pound, uncovered, until the skin is crispy-brown. In order for the skin to become crunchy you will turn the oven up to 400 degrees and cook for an additional 20 to 30 minutes. Let the meat rest on a cutting board for 20 minutes before slicing, (this allows the juices to settle and remain in the meat)Cut the entire roast in 3 inch pieces and season with a mixture of salt, oregano, garlic powder and pepper,(use your hands and toss like a salad) I recommend you first Brine the pork shoulder in 4 tablespoons of salt, pepper, sugar and garlic in a pot of distilled water. Submerge the pork completely in a deep pot (covered) for 12 to 24 hours in the refrigerator. This will ensure a very juicy roast.